Which one should I use for a general 'info@company.com' address?

Use a Shared Mailbox. This allows multiple people to log in, read the emails, and reply directly from the 'info@' address so the customer sees a unified response.

Can external people outside my company email a Distribution List?

By default, no. To prevent spam, Microsoft 365 restricts distribution lists to internal senders only. You must ask IT to explicitly allow external senders for that specific list.

Understanding Distribution Lists, Microsoft 365 Groups, and Shared Mailboxes

Applies to: Microsoft 365, Outlook, Microsoft Teams
Article Type: Informational
Last Updated: 2026-05-18

Summary

This article explains the differences between Distribution Lists (DLs), Microsoft 365 Groups, and Shared Mailboxes — three common ways to send email to multiple people or collaborate in Microsoft 365. Understanding when to use each option prevents confusion, avoids duplicate mailboxes, and helps you request the right resource from IT.

Prerequisites

A Microsoft 365 account.
Basic familiarity with Outlook email.

Instructions

1. What Each Option Does

Distribution List (DL)

A Distribution List is a simple email alias that forwards a message to every member of the list. It does not create a shared mailbox, calendar, or file storage — it is purely a mail delivery mechanism.

Example: Sending an email to [email protected] delivers a copy to every person on the list.
Who manages it: IT typically creates and manages DLs. Some organizations allow owners to add or remove members via Outlook.
Best for: One-way announcements, company-wide emails, or sending to a group without needing a shared workspace.

Microsoft 365 Group

A Microsoft 365 Group is a full collaboration resource. When a group is created, it automatically provisions:

A shared mailbox and calendar (visible in Outlook)
A SharePoint site with a document library
A Planner board
Optionally, a Teams team (every Teams team is backed by a M365 Group)
Example: Creating a group called "Marketing Team" gives the team a shared inbox at [email protected], a shared calendar, a file library, and an optional Teams channel.
Who manages it: Owners can add/remove members. IT may restrict who can create new groups.
Best for: Teams that need to collaborate — share files, schedule meetings, manage tasks, and have threaded conversations.

Shared Mailbox

A Shared Mailbox is a dedicated mailbox that multiple users can access to read and send email. It does not require a separate license and is typically used for role-based or department-level inboxes.

Example: [email protected] or [email protected] — multiple staff members can read, reply, and manage the mailbox.
Who manages it: IT creates and assigns access. Users access it in Outlook without a separate login.
Best for: Customer-facing email addresses, helpdesks, or department inboxes where multiple people need to respond from the same address.

2. Side-by-Side Comparison

Feature	Distribution List	Microsoft 365 Group	Shared Mailbox
Sends email to multiple people	✅	✅	❌ (sends from one address)
Shared inbox	❌	✅	✅
Shared calendar	❌	✅	✅
SharePoint file library	❌	✅	❌
Planner task board	❌	✅	❌
Teams team integration	❌	✅	❌
Members can reply from the group address	❌	✅ (optional)	✅
Requires a license per user	No	No (uses member licenses)	No (up to 50 GB)
Conversations are threaded	❌ (each person gets a separate copy)	✅ (in Outlook Groups or Teams)	✅ (in the shared inbox)
External senders can email it	✅ (if configured)	✅ (if configured)	✅ (if configured)
Self-service member management	Sometimes (owner-managed)	✅ (owners can add/remove)	❌ (IT manages access)

3. How to Choose the Right Option

Use this decision guide to determine what you need:

"I need to send a message to everyone on my team at once." → Use a Distribution List if you only need email delivery and no collaboration features. → Use a Microsoft 365 Group if the team also needs shared files, calendar, or Teams.

"Multiple people need to respond from the same email address (like info@ or support@)." → Use a Shared Mailbox. This is the standard choice for customer-facing or role-based inboxes.

"My team needs a shared workspace with files, tasks, and email." → Use a Microsoft 365 Group. This is the most feature-rich option and is the backbone of every Teams team.

"I have a DL but my team also needs shared files and a calendar." → Ask IT to convert the DL to a Microsoft 365 Group, or to create a new group with the same members. Give them the DL's email address and say whether it must keep working, so mail sent to the old address is not lost.

"I already have a Teams team — do I also need a DL or shared mailbox?" → Probably not. Every Teams team already has a M365 Group with a shared email address. Check if the group email meets your needs before requesting a separate DL or mailbox.

4. How to Access Each Resource in Outlook

Access a Distribution List

You do not "open" a DL — you send email to its address like any other recipient.
To see who is on a DL: In Outlook, create a new email, type the DL name in the To field, then click the + (expand) icon to see individual members.

Access a Microsoft 365 Group

In Outlook Desktop (Classic): Groups appear in the left sidebar under Groups. Click the group name to see shared conversations, calendar, and files.
In Outlook on the Web: Click Groups in the left navigation pane.
In Teams: If the group has a Teams team, access it directly in the Teams app.

Access a Shared Mailbox

In Outlook Desktop: The shared mailbox appears as a separate mailbox in the left sidebar (if IT has granted you access). If it does not appear, see How to Add a Shared Mailbox in Outlook.
In Outlook on the Web: Click your profile icon > Open another mailbox > type the shared mailbox address.

5. Common Scenarios and What to Request from IT

Scenario	What to Request
"We need a company-wide announcement list."	Distribution List (one-way broadcast)
"Our team needs shared files and a channel in Teams."	Microsoft 365 Group (with Teams enabled)
"Multiple people need to reply from [email protected]."	Shared Mailbox
"Customers email [email protected] and 3 agents need to respond."	Shared Mailbox
"We have a DL but also need shared files and a calendar."	Convert DL to Microsoft 365 Group
"A vendor needs to email our project team."	Microsoft 365 Group (enable external senders) or DL

Troubleshooting

DANGER

If you are unsure which resource your team already has, check with IT before requesting a new one. Duplicate groups and mailboxes create confusion, fragmented conversations, and wasted storage.

Symptom / Error	Potential Cause	Solution
Emails to a DL are not being delivered	You are not a member, or external sending is blocked	Contact IT to verify membership and delivery settings.
M365 Group does not appear in Outlook	Group is hidden or you are not a member	Ask the group owner to add you, or contact IT.
Shared mailbox is not in my Outlook sidebar	Auto-mapping is disabled or access not granted	See How to Add a Shared Mailbox in Outlook to manually add it.
Replies from a shared mailbox show my personal name	"Send As" permission not configured	Contact IT to grant "Send As" permission so replies appear to come from the shared mailbox address.
Too many DLs with overlapping members	Organic growth without governance	Request IT to audit and consolidate DLs into M365 Groups where collaboration is needed.
Cannot add external members to a group	Guest access is disabled by policy	Contact IT to enable guest access for your M365 Group.

Understanding Distribution Lists, Microsoft 365 Groups, and Shared Mailboxes ​

Summary ​

Prerequisites ​

Instructions ​

1. What Each Option Does ​

Distribution List (DL) ​

Microsoft 365 Group ​

Shared Mailbox ​

2. Side-by-Side Comparison ​

3. How to Choose the Right Option ​

4. How to Access Each Resource in Outlook ​

Access a Distribution List ​

Access a Microsoft 365 Group ​

Access a Shared Mailbox ​

5. Common Scenarios and What to Request from IT ​

Troubleshooting ​

Related Articles ​

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