Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
what finally worked for me was, even though I couldn't see the field, I just started typing in the key (no dashes) then clicked enter, it took me to another small screen to select settings, which I couldn't see, I clicked enter again.
I was able to get the product key screen to come up multiple times to try this by opening Word, going to Word Options>Resources>activate Microsoft Office