A shared mailbox lets a team send and receive email from a single address like [email protected]. Mailbox delegation gives one person access to another individual's mailbox.
Before you start: You need the Global Administrator role in Microsoft 365. Only people within your organization can be added to a shared mailbox.
Create a shared mailbox
Best for team or department addresses (support@, sales@, info@) that several people monitor together. A shared mailbox doesn't need its own license or password and includes 50 GB of storage.
Sign in to the Microsoft 365 Admin Center.
In the left navigation pane, go to Teams & groups > Shared mailboxes. (If you don't see it, select Show all at the bottom of the menu.)
Select + Add a shared mailbox.
Enter a Name (e.g., Customer Support). The email address fills in automatically from the name — edit it if you'd like (e.g.,
[email protected]). Select Save changes.
Wait a few minutes for the mailbox to be created, then select Add members to this mailbox > Add members. Choose the people who need access and select Save > Close.
Members you add here automatically receive both Full Access (read and manage mail) and Send As (send mail from the shared address). Sign-in is blocked by default no one logs in to the mailbox directly; they reach it through their own account.
Delegate access to an existing mailbox
Best for covering someone's inbox while they're away, or giving an assistant ongoing access. Pick the permission level that matches what the delegate needs to do:
Read and manage (Full Access) — open the mailbox and manage its contents, but not send mail from it.
Send as — send messages that appear to come directly from the mailbox owner.
Send on behalf — send messages that show as "Delegate on behalf of Owner."
You can combine these. For example, Full Access plus Send as lets a delegate manage the inbox and reply as the owner.
Sign in to the Exchange Admin Center.
In the left navigation pane, select Recipients > Mailboxes.
Select the mailbox you want to share. Its details open in a pane on the right.
Open the Delegation tab.
Select Edit next to the permission you want to grant, select + Add members, choose the delegate(s), and select Save.
For end users ,open a mailbox you've been given access to
Outlook (desktop): Nothing to set up. Auto-mapping adds the mailbox to the bottom of your folder list automatically.
Outlook on the web:
Sign in at Outlook on the web.
Right-click Folders in the left navigation pane.
Select Add shared folder or mailbox.
Enter the mailbox name or address and select Add.
Troubleshooting
Permission changes can take 15–60 minutes to take effect. If the mailbox doesn't appear, wait an hour, then close and reopen Outlook.