Press and hold the Power button
Tap Power off
If prompted, tap Power off again to confirm
If the Power menu does not appear, press and hold the Power button and Volume Up button together
If the phone is frozen, press and hold the Power button for 10 to 20 seconds until it turns off
On some phones, swipe down the Quick Settings panel and tap the Power icon
On some Samsung phones, press and hold the Side button and Volume Down button, then tap Power off
If needed, use the Settings app and search for Power off or Shutdown