This applies to Outlook for Mac 2016 and 2019 on macOS Sierra and above. We have not tested it outside of those parameters.
- In Outlook for Mac, select Outlook > Preferences on the menubar.
- Select the Accounts panel from the top row.
- Click the + at the bottom of the Accounts list in the lower-left corner of the screen. Select 'New Account'.
- On the dialog that opens, enter the email address of the account you are adding. Click [Continue].
- Microsoft will verify the account exists and then ask for your password. Don't type your password yet. Below the password field, click on "Sign in with another account".
- The dialog will refresh. Replace the email address on this screen with your email address. Click [Next].
- Enter your password. Click [Sign in]. If you have Multi-Factor Authentication, you should be prompted for that.
- The mailbox will add to Outlook as a separate mailbox.
If there are any issues with this procedure, please send an email to us at email@example.com