Use AssistiveTouch on Vsmart smartphone
You can use AssistiveTouch to adjust volume, lock your screen, capture your screen or turn on flash led
When you turn on AssistiveTouch, you'll see a button appear onscreen. You can drag it to any edge of the screen, where it will stay until you move it again. By default, tapping the button once will open the AssistiveTouch menu. Tapping once anywhere outside of the menu will close it.
Step 1: Go to setting
Step 2: Tap on “Accessibility”
Step 3: Tap on “Assistive Touch”
Step 4: Enable “Use service”
Step 5: Allow to use Assitive Touch