Allow User, Access to Another User's Mailbox - Admin Help

This guide explains how administrators can grant mailbox access in Exchange Online and Outlook using Microsoft 365 tools.

Prerequisites

• You must be assigned the Exchange Administrator or Global Administrator role in Microsoft 365.
• Ensure the target mailbox is active and licensed.

Here's how you will be able to enable the access.

First, decide the level of permission you want to allow the other user to take in the given mailbox.

You can allow a user to read emails from the mailbox, send emails on behalf of another user, and send emails as if they were sent from that mailbox.

Send email from another user's mailbox

1. In the admin center, go to the Users > Active users page
2. Select the name of the user (from whom you plan to give a sending permission) to open their properties pane.
3. On the Mail tab, select Manage mailbox permissions.
4. Next to Send as, select Edit.
5. Select Add permissions, then choose the name of the person who you want this user to be able to send as.
6. Select Save.

Read email in another user's mailbox

1. In the admin center, go to the Users > Active Users page.
2. Select the name of the user (whose mailbox you want to allow to be read) to open their properties pane.
3. On the Mail tab, select Manage mailbox permissions.
4. Next to Read and manage, select Edit.
5. Select Add permissions, then choose the name of the user or users that you want to allow to read email from this mailbox.
6. Select Save.

Send email on behalf of another user

1. In the admin center, go to the Users > Active Users page
2. Select the name of the user (from whom you plan to give a Send on behalf permission) to open their properties pane.
3. On the Mail tab, select Manage mailbox permissions.
4. Next to Send on behalf, select Edit.
5. Select Add permissions, then choose the name of the user or users that you want to allow to send email on behalf of this mailbox.
6. Select Save.

Please note: Once you've set up the permissions, it may take up to 60 minutes for the changes to propagate through the system and be in effect.