If you have Office 365, then whenever Microsoft botches an update or has server issues, you have no Office. If you have Office 365, it is probably 64 bit. This can be an issue if you use macros or Access databases. I normally recommend 32 bit Office to avoid issues. 32 bit Office runs fine on 64 bit Windows. Unless you are using Excel spreadsheets that have millions of rows, you probably do not need the 64 bit version. I also do not use Office 365, but Office 2016 or 2019 to avoid issues when Microsoft has problems.
How to tell what version of Office 365 you have: