Press and hold the Power button until the power menu appears
Tap Power off
If prompted, tap Power off again to confirm
If the screen is frozen, press and hold the Power button and Volume Down button together for about 10 to 20 seconds until the phone turns off
On some phones, press and hold the Power button and select Power off from the menu
On some Samsung phones, press and hold the Side key and Volume Down button, then tap Power off
If your phone has a removable battery, remove the back cover and battery to turn it off