When iOS 9.3 was launched, the two biggest new features on the iPhones, were Night Shift and the ability to lock your Notes on the device. Night Shift is fairly easy to turn on, and in fact, slotted right into your Control Center. However, locking your Notes app is a bit of a tricky thing to do. In fact, if we are to be absolutely correct, then you cannot lock the Notes app in itself. You can only lock certain Notes within the application which will then be accessible only after you have put the fingerprint that the phone recognises via Touch ID.
In order to lock a select few Notes, you need to launch the Notes app first and jot down a new Note in there. You can also, just simply open an old Note that you may want to protect and lock away. Once you are done scribbling away, you need to click on the Share icon, and from the share sheet that opens, select the option of ‘Lock Note’.
Once you do that, you will be asked to set a password and verify the same. You will have to input the Hint too and once all of this is in place, make sure you have the usage of Touch ID set to ‘On’.
Now, the next time, you try to open the same Note in the application, you will be prompted to either enter the password or use the Touch ID. We really wish Apple would have made the feature application wide, where you could just simply lock the app, but guess that it would take another OS release for the same.