Microsoft-Office-For-MacOS

Tutorial: Remove Office License and Install a new Office Volume License using Serializer

First, log off every account that logs on to Microsoft Word.

Second, download this and install it. You won't get any new apps but after running it will clear your Office license. License Removal Tool

Last, download this and install it. You won't get new apps but this will activate your Office. Serializer

You will get the Office 2021 now.