Apple Notes sharing works (mostly) flawless and so does the changes review on the shared notes.
It’s easy to lose track of all the changes made to your notes if it happens to share those notes with others.
People that have access to the same notes can add end erase things and things can get confusions pretty fast.
That’s why Apple Notes maintain a log for all the recent changes, so you can see who, when and what did on a shared note.

It’s actually pretty easy to acces the changes log on an iPhone or iPad. You just have to swipe right on a shared note.
You see the changes with their respective timestamps and authors on the left side of the screen.
Swipe left to hide the changes log and go back to your note.
The feature works in a similar way on Macs, except you’ll do the swiping with two fingers on the trackpad.