Password for locking Noted
If you know your old password, then it is quite straight forward to change your password. 

In addition, you can reset your password, but this won’t give you access to your old notes. It will, however, let you password protect any notes that you create from that point forward with the new password. This could lead to you having multiple notes with different passwords.


On your iOS device, tap Settings





Tap Notes

 
Tap Password


You will see a Changed Password option. You can change your password if you know the original password. The other option is “Reset Password”. Tap Reset Password.


You will have to enter your Apple ID password and tap OK.