This guide will allow you to turn on assistive touch on your iPhone to help you if you can't use iPhone's physical buttons or gestures.
Step 1: Launch Settings
Tap the settings icon on your iPhone.
Step 2: General
Tap General to open general settings.
Step 3: Accesbility
Step 4: Tap Assistive Touch
Tap Assistive touch and then toggle the switch to on to enable it. Then the little white circle will be on your screen at all times, then you can move it by dragging it another area on your screen if needed. Tapping the circle will open up a number of options, helping you if you are unable to use iPhone's physical gestures such as home button, shaking, and lock button.