Press and hold the power button until the power menu appears
Tap Power off or Turn off
If prompted, confirm the action
If your phone uses button combinations, press and hold the power button and volume up or volume down button together
If the screen is frozen, press and hold the power button for 10 to 20 seconds until the phone shuts down
If your phone has no physical power button, open Quick Settings or Settings and select Power off
If needed, wait for the screen to go completely black to confirm the phone is off