I would like to approve credit memos prior to posting. Is this a BPM?

Hey Brian, welcome to the group!

You are correct: there is no built-in function that allows a person to create a CM (or any other invoice) yet not post it.

So, yes, you’d need a BPM to do this.

EDIT:
Ah, that’s right, there was a similar discussion recently - though this was AP, not AR.