How do you upgrade apps to 64 bit ?

You may not know until your upgrade unless you check the apps that you use and see if the company provides 64-bit versions for Mac.

For example. Adobe Creative Suite does not fully support 64-bit applications, but Adobe Creative Cloud does.

Download and run this free utility.

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

It will tell you which apps you currently use that are 32 bit.