Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi. I'm Brian and I will do my best to help you.
Which Outlook? Classic or new? For Windows? iOS? Android? Details make a difference.
If you're using classic Outlook, FIle>Add Account works just fine. If you're using new Outlook, Settings>Accounts>Email accounts>Add account. If you access Outlook using a web browser, you can't add another account to that mailbox.