How to uninstall the Office completely and ensure all the previous settings and license information are gone?

I ve been trying to uninstall my unlicensed Office 2016 Professional Plus then re-installing Office 365 Business instead. However, every time I re-installed it, I still see the pop up window saying that my 2016 Professional Plus is unlicensed, which is really annoying. All my previous settings (apps pinned on the Start menu, files that I opened previously, my Outlook settings, etc) remained unchanged after the re-installation, which is not what I expected. How can I actually uninstall the Office completely and make sure all the previous settings and license information are cleared when I uninstall it?