How to add a shared inbox to Outlook
To add a shared inbox to Outlook, a Microsoft 365 admin creates a shared mailbox and grants your team access; it then shows up in each person's Outlook automatically.
A shared mailbox in Microsoft 365 lets several people read and reply from one address, like [email protected], without paying for an extra license. Once an admin sets it up and adds members, it appears in Outlook next to their own mailbox, and replies go out from the shared address instead of a personal one.
It is the right first step for a small team that just wants one place for support email. Where it runs out of road is tracking: a shared mailbox does not show who is replying to what, so two people can answer the same email, and nothing tells you which messages still need a reply.
Steps
- 1
Sign in with an Exchange admin account
You need the Exchange admin role (Global admin also works) in your Microsoft 365 tenant. If you're not an admin, ask whoever manages your Microsoft 365 subscription; there's no user-level way to create one.
- 2
Open Shared mailboxes in the admin center
In the Microsoft 365 admin center, expand Teams & groups in the left nav and select Shared mailboxes. (Select "Show all" first if Teams & groups is collapsed.)
- 3
Add the mailbox
Select "+ Add a shared mailbox," give it a display name (e.g. "Customer Support"), and set the email address (e.g. [email protected]). Save. It can take a few minutes before you can add members.
- 4
Add members
Under "Next steps," select "Add members to this mailbox," then "+ Add members" and choose everyone who should see incoming mail and replies. This is what actually gives people access. The mailbox alone does nothing.
- 5
Wait for it to appear in Outlook
With auto-mapping on (the default), the shared mailbox shows up in each member's Outlook automatically after they close and reopen the app, usually within an hour, occasionally up to a day. If it doesn't show up, add it manually: in Outlook, right-click your account in the folder pane, choose "Add shared folder or mailbox," and search for it by name.
- 6
Reply from the shared address
When you compose or reply, set the From field to the shared address so the customer sees [email protected], not your personal email. If From is hidden, enable it from the Options menu.
Frequently asked questions
What’s the difference between Full Access, Send As, and Send on Behalf?
Full Access lets someone open and manage the mailbox but not send from it. Send As lets them send mail that appears to come directly from the shared address. Send on Behalf sends as "[Name] on behalf of [Mailbox]," showing who actually sent it. Full Access is required either way; Send As or Send on Behalf is what actually lets someone reply.
What’s a simpler option if I don’t have Microsoft 365 admin access?
A dedicated shared-inbox tool like AcornReply sidesteps the admin center entirely: forward your support address to a per-workspace inbound address (no DNS changes) and your team gets one shared inbox with assignment, status, and AI-drafted replies, with no Exchange admin role and no waiting on auto-mapping. It’s a separate tool, not a Microsoft 365 feature, and it doesn’t give you a shared calendar the way an Outlook shared mailbox does.