Summary

This guide takes you from "I have a domain name and a credit card" to a working Microsoft 365 setup: the right plan, business email on your own domain, an account for every person, multi-factor authentication switched on, the apps installed, and a shared place for company files. Budget about 30 minutes of clicking spread across a day or two — the rest of the time you are waiting on DNS.

In this guide

• 1. Choose your plan before you sign up
• 2. Sign up and get your temporary onmicrosoft.com domain
• 3. Connect your own domain
• 4. Create your users and pick the right home for info@
• 5. Assign licenses and check what you are paying for
• 6. Turn on multi-factor authentication for everyone
• 7. Install the apps and turn on OneDrive
• 8. Create a SharePoint site for shared files
• 9. Work through the before-you-finish checklist

Before You Start

• A domain name you own, plus the sign-in details for the company you bought it from (GoDaddy, Namecheap, Cloudflare, Squarespace, and so on). If you do not own one yet, Microsoft can sell you one during signup.
• A credit card or bank card for the subscription.
• A phone that can run the Microsoft Authenticator app.
• Nobody needs to grant you admin rights. The account you create during signup becomes the Global Administrator of your new tenant automatically.

Instructions

1. Choose your plan before you sign up

Changing plans later is possible, but picking correctly now saves you a migration and a refund conversation. All three Business plans cap out at 300 users, which no five-person business will hit.

• Business Basic — business email on your domain, 1 TB of OneDrive per person, Teams, and the web and mobile versions of Word, Excel, Outlook, and PowerPoint. No installed desktop apps.
• Business Standard — everything in Basic, plus the full desktop apps installed on up to five computers per person, webinar hosting, and Microsoft Bookings.
• Business Premium — everything in Standard, plus device management and the security tooling that lets you wipe a lost laptop remotely.

For most 1–5 person businesses, Business Standard is the right default: the desktop version of Excel and Outlook is meaningfully more capable than the browser version, and the price gap is small. Pick Business Basic when everyone genuinely works in a browser all day. Pick Business Premium when you handle client data that carries a regulatory obligation, or when you issue company-owned laptops you would need to wipe remotely.

For a full feature-by-feature comparison, read Understanding Microsoft 365 Business Basic vs Standard and Understanding Microsoft 365 Licensing and Plan Differences. If you have not settled on Microsoft at all yet, Understanding Microsoft 365 vs Google Workspace for a One-Person Business covers that decision.

Tip: Annual billing costs roughly 20% less than paying monthly for the same plan. Start monthly while you are still deciding, then switch to annual once the setup is settled — you can change billing frequency later under Billing > Your products.

2. Sign up and get your temporary onmicrosoft.com domain

Signing up creates your tenant — Microsoft's word for your company's private area of its cloud. Everything else in this guide happens inside it.

1. Go to microsoft.com/microsoft-365/business and select your plan. Click Try free for one month or Buy now.
2. Enter an email address you already control (a personal Gmail or Outlook address is fine here). Microsoft emails you a verification code — type it in and click Next.
3. Fill in Tell us about yourself: your name, business name, phone number, and country. The country you pick cannot be changed later and determines which data centre holds your mail, so pick the country you actually operate in.
4. On the How you'll sign in page, Microsoft asks you to create a username and pick a domain. Choose Get a new domain to buy one from Microsoft, or take the free option and use the .onmicrosoft.com domain it offers.
5. Type the name you want in the domain box — for example northfieldjoinery. Microsoft creates northfieldjoinery.onmicrosoft.com and your first sign-in becomes [email protected].
6. Enter your payment details and complete the purchase. A confirmation page appears with a Get started button, and you land in the Microsoft 365 admin center at admin.microsoft.com.

Note: That .onmicrosoft.com domain is permanent. It cannot be renamed or removed, so pick a name you would not mind a client seeing. It stays useful as a fallback — if your custom domain's DNS ever breaks, you can still sign in with the .onmicrosoft.com address.

Verification: Open admin.microsoft.com in a browser. If you see the Microsoft 365 admin center home page with Users, Billing, and Settings in the left navigation, your tenant exists and your account is a Global Administrator.

3. Connect your own domain

This is the step that turns [email protected] into [email protected]. You do it in two places at once: the Microsoft admin center in one browser tab, your domain registrar in another.

1. In the Microsoft 365 admin center, click Settings in the left navigation, then Domains. If you do not see Settings, click Show all at the bottom of the navigation first.
2. Click Add domain at the top of the Domains list, type your domain (for example northfieldjoinery.co.uk), and click Use this domain.
3. Microsoft asks you to prove you own it. Select Add a TXT record to the domain's DNS records and click Continue. It displays a TXT value beginning MS=.
4. In your other browser tab, sign in to your registrar and open its DNS or DNS Management page. Add a new TXT record with the host set to @ and the value Microsoft gave you, then save.
5. Return to the Microsoft tab and click Verify. When it succeeds, the wizard moves on to the mail records.
6. Choose Add your own DNS records, then add the MX, CNAME, and TXT (SPF) records Microsoft lists, copying each value exactly. The MX record routes incoming mail, the CNAME lets Outlook configure itself, and the SPF record stops your mail being treated as spam.
7. Click Continue. Microsoft re-checks the records and marks the domain Healthy in the Domains list.

Verification: Back in Settings > Domains, your domain shows a green Healthy status and the label (Default) once you set it as primary. New users you create now offer your real domain in the username dropdown.

For the registrar-by-registrar detail — including what to do when your website lives at the same domain — follow How to Set Up Email on a Custom Domain in Microsoft 365. Once mail is flowing, Understanding Email Security (SPF, DKIM, DMARC) in Plain English explains the three records that decide whether your invoices reach the inbox or the junk folder.

Set honest expectations here. Your registrar saves the record in seconds. Microsoft's verification check usually passes within 15 minutes. Full propagation across every mail server on the internet takes up to 48 hours, and during that window some senders reach your old mailbox and some reach the new one. That is normal, not a fault — and it is exactly why you migrate existing mail before you change the MX record, not after. How to Migrate from Google Workspace to Microsoft 365 covers the order of operations if you are coming from Gmail.

4. Create your users and pick the right home for info@

Every person who needs an email address gets an account. Every address that no person signs in as gets a shared mailbox instead.

To add a person:

1. In the admin center, click Users in the left navigation, then Active users.
2. Click Add a user at the top of the list.
3. Fill in First name, Last name, and Display name. In the Username box, type the part before the @, then pick your custom domain from the dropdown beside it.
4. Under Password settings, choose Auto-generate password and leave Require this user to change their password when they first sign in ticked. Tick Send password in email upon completion and enter your own address so you can pass it on securely.
5. Click Next, assign a license on the Licenses and apps page, click Next twice more, then click Finish adding.

For info@, sales@, accounts@, or hello@, create a shared mailbox rather than a user account:

1. In the admin center, click Teams & groups, then Shared mailboxes.
2. Click Add a shared mailbox, enter a name such as Enquiries and the address [email protected], and click Save changes.
3. Click the new mailbox in the list, then Edit next to Members, and add the people who need to read and reply.

	User account	Shared mailbox
Costs a license	Yes	No
Somebody signs in as it	Yes	No
Storage	50 GB or more	Up to 50 GB
Has its own OneDrive and Teams identity	Yes	No
Several people read and reply	Awkward	Built for it

The rule of thumb: if no human ever types that address into a sign-in box, make it a shared mailbox. Replies still go out from info@, so customers never see who answered. How to Set Up a Shared Inbox for a Small Business covers how to work in one day to day, including how to send as the shared address.

5. Assign licenses and check what you are paying for

A user without a license has an account but no mailbox — mail sent to them bounces. Check this before you hand out passwords.

1. Go to Users > Active users and click a person's name. A panel slides in from the right.
2. Click the Licenses and apps tab.
3. Tick the subscription you want to assign, then click Save changes. The panel confirms the change and the mailbox is created within a few minutes.
4. To see the whole picture at once, go to Billing > Licenses. Each subscription row shows Assigned against Total.
5. If you are short of seats, go to Billing > Your products, click the subscription, then Buy licenses, and set the new quantity.

Note: Buying a seat and assigning a seat are two separate actions. Buying alone changes your bill without giving anyone a mailbox. Assigning alone fails with "no available licenses" if you have none spare.

How to Manage Microsoft 365 Subscriptions and Billing covers invoices, switching to annual billing, and the trap where a departing employee keeps costing you money.

6. Turn on multi-factor authentication for everyone

Do this on day one, before anyone has time to build habits around a password-only sign-in.

This is not optional and it is not paranoia. Your Microsoft 365 account is the recovery address for your bank, your accounting software, and your domain registrar. An attacker who reads your mail can redirect an invoice payment, and business email compromise is the single most common way small businesses lose money to fraud. Microsoft now enforces MFA for admin center sign-in regardless, so the only real decision is whether the rest of your team gets the same protection.

The fastest route for a small business is security defaults, a single switch that requires MFA for everyone and blocks the oldest, least secure sign-in methods.

1. Go to entra.microsoft.com and sign in with your admin account. This is the Microsoft Entra admin center — the identity portal that sits behind Microsoft 365.
2. In the left navigation, click Identity, then Overview.
3. Select the Properties tab across the top of the page.
4. At the bottom of the Properties page, click Manage security defaults.
5. A panel opens on the right. Set Security defaults to Enabled, choose a reason if prompted, and click Save.

Every account now has 14 days to register. At their next sign-in, each person sees a More information required prompt that walks them through installing Microsoft Authenticator and scanning a QR code. Tell your team it is coming, or the prompt looks exactly like a phishing page.

Verification: Sign out completely, then sign back in to admin.microsoft.com from a private browser window. You are prompted to approve the sign-in on your phone. If you are not, security defaults did not save — repeat step 5.

If Manage security defaults is greyed out with a note about Conditional Access, your tenant already has policies in place and security defaults are blocked by design. That happens on Business Premium tenants. In that case, build the equivalent as a Conditional Access policy instead.

Understanding Multi-Factor Authentication (MFA) for Small Business explains what your team is agreeing to and how to answer the "will this slow me down every morning" objection. Pair it with How to Set Up Self-Service Password Reset (SSPR) so a forgotten password does not become your problem at 7am.

7. Install the apps and turn on OneDrive

Business Standard and Business Premium include the installed desktop apps. Business Basic does not — on Basic, everyone works at microsoft365.com in a browser and this step is a five-minute sign-in instead.

1. On each computer, open a browser, go to microsoft365.com, and sign in with the work account.
2. Click Install apps in the top right of the home page, then Microsoft 365 apps. A setup file downloads.
3. Run the downloaded file and wait. The installer shows a progress animation, then a You're all set! message. Word, Excel, PowerPoint, Outlook, and Teams appear in the Start menu.
4. Open Outlook. It finds the account from the sign-in you already did and offers to add it — click Continue, and the mailbox syncs.
5. Open OneDrive from the Start menu. Sign in with the work account when prompted, then click Next through the introduction screens.
6. When OneDrive offers Back up folders on this PC, leave Desktop, Documents, and Pictures switched on and click Start backup. Those folders now sync to the cloud, which means a stolen laptop is an inconvenience rather than a disaster.

Verification: Open File Explorer. A cloud icon with your business name appears in the left sidebar, and files inside it show a green tick once synced.

How to Set Up Microsoft 365 on a New or Personal Device is the page to send each new hire. Understanding Microsoft 365 Apps — What Each App Does and When to Use It is worth forwarding too, because most of the apps in that launcher are ones nobody has heard of.

8. Create a SharePoint site for shared files

OneDrive is personal storage. Anything the business owns — contracts, templates, client folders, the accounts spreadsheet — belongs in SharePoint, so it survives the person who created it leaving.

1. From any Microsoft 365 page, click the app launcher (the grid of dots in the top-left corner) and choose SharePoint.
2. Click Create site near the top of the page.
3. Choose Team site. A panel opens asking for a Site name — use something durable like Company Files rather than a project name.
4. Add a short description, click Next, pick your language, then click Create.
5. On the Add members screen, type each person's name and click Finish. Everyone you add gets edit access to everything in the site.
6. In the left sidebar of the new site, click Documents. Create top-level folders that match how your business thinks — for example Clients, Finance, Templates, Insurance.
7. With the Documents library open, click Sync in the command bar at the top. After a moment, the library appears in File Explorer under your business name, alongside OneDrive.

Tip: Prefer Add shortcut to OneDrive over Sync if people work across several computers. The shortcut follows the account rather than the machine, so a new laptop gets the shared folders the moment OneDrive signs in.

How to Set Up a Shared Drive or Team Folder for a Small Group goes deeper on folder structure and permissions. If the OneDrive-versus-SharePoint-versus-Teams distinction still feels blurry, Understanding Where Your Files Live — OneDrive vs. SharePoint vs. Teams settles it.

9. Work through the before-you-finish checklist

Run through this list before you close the admin center and get back to your actual job. Each item takes under a minute and each one is something small businesses routinely discover six months too late.

• Send a test email from an outside address to every new mailbox, including the shared ones, and confirm it arrives. Reply to each and confirm the reply lands.
• Confirm MFA is registered on every account, not merely enabled. Go to Users > Active users and check that nobody is still inside the 14-day grace window.
• Create a second Global Administrator account. Give it its own license-free existence if you like, store the password in a password manager, and register a different phone for MFA. This is the single thing that prevents one lost phone locking you out of your own business.
• Set your custom domain as the default in Settings > Domains, so new accounts default to the right address.
• Check Billing > Licenses and confirm assigned seats match your headcount. No empty seats.
• Confirm OneDrive folder backup is on for every computer, and that at least one file shows a green tick.
• Decide where invoices and contracts live and tell everyone. A shared site nobody knows about is not a shared site.
• Add your accountant's email to Billing as a notification recipient under Billing > Bills & payments so invoices reach them directly.
• Write down your recovery details — the .onmicrosoft.com address, the second admin account, and your registrar login — and store them where a family member could find them.

Microsoft 365 backs up its own service, but it does not protect you from a file you deleted on purpose 90 days ago. How to Back Up Business Data When You Don't Have IT explains what the built-in retention actually covers and where you still need your own copy.

Troubleshooting

WARNING

The moment your new MX record takes effect, every message sent to your domain goes to Microsoft 365 — and nowhere else. Move your existing mail across before you change the MX record, and keep the old mailbox open and monitored for at least 72 hours afterwards so nothing sent during the changeover is lost.

Symptom / Error	Potential Cause	Solution
Microsoft says domain verification failed	DNS record not published yet	Wait 15 minutes and click Verify again. Confirm the TXT host is @ and that your registrar did not append your domain name to the value.
Mail arrives, but the mailbox is empty of old messages	Existing mail was never migrated	Nothing moves automatically. Import a PST in Outlook, or run a migration from Setup > Migrate email — see Step 3.
Your emails land in recipients' junk folders	SPF record missing or wrong	Check the TXT record at your registrar reads exactly v=spf1 include:spf.protection.outlook.com -all, with no second SPF record alongside it.
A new user cannot sign in	No license assigned, or replication delay	Assign a license as in Step 5, then allow 15 minutes. A brand-new account is not usable the instant you click Finish adding.
Manage security defaults is greyed out	Conditional Access policies exist	Security defaults are blocked when Conditional Access is in use, which is normal on Business Premium. Build an equivalent Conditional Access policy instead.
A shared mailbox does not appear in Outlook	Automapping has not caught up	Close and reopen Outlook. If it is still missing after two hours, remove and re-add the member in Teams & groups > Shared mailboxes.

Related Articles

• Understanding Microsoft 365 Business Basic vs Standard
• Understanding the Microsoft 365 Admin Center for Non-IT Owners
• How to Set Up Email on a Custom Domain in Microsoft 365
• How to Add or Remove Users in Microsoft 365 Admin Center
• Understanding Multi-Factor Authentication (MFA) for Small Business
• How to Set Up a Shared Inbox for a Small Business
• How to Manage Microsoft 365 Subscriptions and Billing
• How to Back Up Business Data When You Don't Have IT

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