As a side note:
1. If I create a program in Access 2021, will it work correctly with Office 365?
2. If created in 32 Bit and I add PtrSafe, will it work under question 1 above

There is an advanced method to copy VBA from, say, a text box and insert your code into a new module.

1. Yes

2. PtrSafe is generally intended for compatibility with 64 bit systems. However, you could use the following code to put a PtrSafe function in a 32-bit module:

#If VBA7 Then
Declare Function DoSomething
#Else
Declare PtrSafe Function DoSomething
#End If

If the statement turns red, the VBA editor compiles and executes the statement just fine, but VBA is intended to read either 32-bit or 64-bit, dependent on which bitness version you have installed on your machine, you usually can’t use both on the same database file, however the code declarations I posted above helps get around that limitation.