Tap tap. Take a screenshot. Or go to the Home Screen. Or open Control Center. You can set up Back Tap to perform an action when you double-tap or triple-tap the back of your device.
To learn more about this topic visit the following articles: Use Back Tap on your iPhone: apple.co/3CMaNVN Tap the back of iPhone to perform actions or shortcuts: apple.co/3GQpn0W Run shortcuts by tapping the back of your iPhone: apple.co/3mJzRqF