Step 1: First step is to open elevated Command Prompt. To do so, you can simply type CMD in the Start screen or Start menu search box and then press Ctrl+Shift+Enter key.
Alternatively, you can navigate to Command Prompt entry in the Start menu or Start screen, right-click on Command Prompt, and then click Run as administrator option.
If you’re running 32-bit version of Office 2016 on 64-bit Windows, please use the following command:
cscript “C:\Program Files (x86)\Microsoft Office\Office16\OSPP.VBS” /inpkey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
In the above command, replace XXXXX-XXXXX-XXXXX-XXXXX-XXXXX with the new key that you would like to use.
Once the key is successfully updated, you’ll see “Product key installation successful” message. That’s it!