Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi Sara! I'm Stephen, an Independent Advisor here in the Microsoft Answers Community.
You can check out this link below to get you started with Microsoft Office Pro.
https://www.microsoft.com/en-us/p/office-profes...
If you have installed a Microsoft Office Business a long time ago. The message will definitely shows and will direct you at office.com/setupkey.
You try this link below to help you Where to enter your Office product key.
https://support.office.com/en-us/article/where-...
Hope this helps! Please feel free to reply to this message. I'm willing to help you with your concern.