Swipe down from the top of the screen to open Quick Settings
Tap the Flashlight or Torch icon to turn it off
If the icon is not visible, swipe left or right in Quick Settings to find it
Open the Camera app and turn off any flashlight or torch option if enabled
Use the power button or lock screen shortcut if your phone supports flashlight controls there
Ask Google Assistant to turn off the flashlight
If the flashlight stays on, restart the phone