Creating and Managing Shared Mailboxes in Office 365

2 February 11, 2025

Shared mailboxes in Office 365 allow multiple users to access and manage emails from a single mailbox, making them ideal for team communication and customer support. This guide explains how to create, configure, and manage shared mailboxes in Office 365.

Requirements

  • Admin access to the Microsoft 365 Admin Center.
  • An Office 365 license for users who will access the shared mailbox (though the mailbox itself does not require a license).

Step 1: Create a Shared Mailbox

Using the Microsoft 365 Admin Center

  1. Log into the Microsoft 365 Admin Center
  2. Navigate to Shared Mailboxes
    • In the left-hand menu, go to Teams & groups > Shared mailboxes.
  3. Create a New Shared Mailbox
    • Click + Add a shared mailbox.
    • Enter a Name and Email address for the shared mailbox (e.g., [email protected]).
    • Click Save changes.
  4. Assign Users to the Shared Mailbox
    • After creating the mailbox, click Edit under Members.
    • Click + Add members and select the users who need access.
    • Click Save to apply the changes.

Step 2: Configure Shared Mailbox Settings

Grant Additional Permissions

By default, users added to a shared mailbox have Full Access and Send As permissions. If you need to modify these permissions:

  1. In the Shared mailboxes section, select the mailbox you created.
  2. Click on Manage mailbox permissions.
  3. Assign permissions as needed:
    • Full Access: Allows users to open and manage emails in the shared mailbox.
    • Send As: Users can send emails as if they were the shared mailbox.
    • Send on Behalf: Emails will show “sent on behalf of” the shared mailbox.
  4. Click Save to apply the changes.

Step 3: Access the Shared Mailbox

In Outlook Web App (OWA)

  1. Log into https://outlook.office.com.
  2. Click on your profile picture at the top-right and select Open another mailbox.
  3. Enter the name of the shared mailbox and click Open.

In Outlook Desktop App

  1. Open Outlook and go to File > Account Settings > Account Settings.
  2. Select your account and click Change > More Settings.
  3. Navigate to the Advanced tab and click Add.
  4. Enter the shared mailbox email address and click OK.
  5. Restart Outlook, and the shared mailbox will appear in the left-hand panel.

Step 4: Convert a Regular Mailbox into a Shared Mailbox (Optional)

If you need to convert an existing user mailbox into a shared mailbox:

  1. Go to Users > Active users in the Admin Center.
  2. Select the user whose mailbox you want to convert.
  3. Click Convert to shared mailbox and confirm.
  4. Remove the Office 365 license if the user is no longer active (shared mailboxes do not require a license unless over 50GB).

Best Practices

✅ Monitor Storage Limits – Shared mailboxes have a 50GB limit unless assigned a license.
✅ Use Rules & Auto Replies – Set up automatic replies and rules to streamline email management.
✅ Review Access Regularly – Periodically review and update who has access to the shared mailbox.