Assistive Touch is a handy utility that makes your life easier by offering you quick access to useful functions. 

Assistive Touch provides you with easy and quick access to functions such as taking a screenshot, launching your camera, going to the control center, switching on/off Wi-Fi, turning on/off Bluetooth, and more.

The way that it works is by creating a tap gesture that you can use to trigger the desired function. 

For instance, to take a screenshot, you can use a tap gesture that looks like a screenshot, and it will automatically be captured and saved to your gallery.