If you already

If you already

 have the S-Pen in your hand, press and hold the button to enable Screen Off Memo. 

Using the S-Pen, create a note on the lock screen. Once done, tap on the save button at the top right corner. 

One UI saves the note to the phone's memory. You can access it by unlocking your phone and opening the Samsung Notes app. 

Another hidden feature for Galaxy phones

The Screen Off Memo is an amazing hidden feature that allows you to write down your thoughts, but it's exclusive to Galaxy Note or the Galaxy S22/S23 Ultra. What about other Galaxy smartphones? Is there a hidden lock screen for them? With One UI 5.0, Samsung has released the Touch and Hold Edit feature, allowing you to edit the home screen without opening the Settings app on your Galaxy phone.