UpdaTE TO 64 BIT

You can see what Apps might need it...

Go64...

https://www.stclairsoft.com/Go64/

For MS Office, Look into the Free LibreOffice, it handles MS Office files…

https://www.libreoffice.org/

Feature Comparison of LibreOffice v6.3 with Office 365/Office 2019 for Mac

https://wiki.documentfoundation.org/Feature_Comparison:_LibreOffice_-_Microsoft_Office

Update what? Apple computers have been 64 bit for over a decade. If you are asking about a third party app contact the app developer.