It's a setting (toggle) in settings > display to prevent accidental touches on display. It is not perfect but it detects abnormal touches like palm touches and then locks the display. You can turn in off if it gets annoying 😊
Its a function to prevent your screen waking up when its in your bag or pocket. It detects that its in the pocket, if not the phone will unlock and u will be sending messages and calling people from ur pocket without knowing
