How to create password-protected Notes in iOS 9.3

The first step is simply to create or select a regular Note, unsecured note in the app, since notes can only be secured after the fact.

Type some matter on a new note.

Once this is done, tap the Share icon in the upper-right corner of the screen.This is where the "Lock Note" option is hidden, alongside other choices like Copy and Print.

Selecting it brings up a panel asking you to create a password and retype it to verify. For the best security, avoid reusing an existing password, and make the new one either a phrase or a complex assortment of characters. Optionally you can enter a hint in case you forget, and/or use Touch ID to make logins faster.

At this point, a note's contents will still be visible to anyone able to unlock your device. Protection only takes effect once you tap the padlock icon, again in the upper-right corner.

Finally, the note is secure. To see inside, you'll have to tap "View Note" or the padlock icon, and either enter your password or use Touch ID.