Did you open the Notes app and find out that all of the notes have been disappeared from your iOS device after a system update? It happens quite a lot to people but it is not known why it happens.
Users don’t delete the notes but they still get misplaced or sometimes get deleted. For some users, there may be something very important in a note and they want to get their notes back.
Regardless of how you lost your notes, there is still a chance that you can get them back. There are a couple of ways by which you can try to recover the deleted or misplaced notes.