Forgot note’s password

Lock or unlock notes on your iPhone or iPad - Apple Support

Scroll down to the section about resetting your password. Please note that if you created a custom password and forget it you are out of luck and cannot ever recover those notes. Good Luck

Unfortunately, until you remember the locked notes password you created when you locked the notes, they will remain locked. The password is fully encrypted on the phone and no one, not Apple, nor anyone here can help you. You can guess as many times as you want, but you and only you have the ability to unlock them.

You can create a new locked notes password for future notes you create. But you cannot change, nor open the notes which are locked with the password you cannot remember.

You should write down important passwords somewhere safe for future recall.