There are two ways of navigate note history on iOS and iPadOS. The first one is using the history navigation controls available in the more (⫶) menu inside the note. The navigation bar will appear on top of the note.

You can also use these navigation options even faster by swiping with two fingers from any edge of the screen. Swipe right to go to your previous note, swipe down to go to the top of a note, and so on.