How to Enable Back Tap on iPhone
You can now tap on the back of your iPhone to perform different actions. If your iPhone is running on iOS 14, then you can use back tap, here's how.
Now head over to the Accessibility Settings then tap on Touch.
Enable Back Tap
Now scroll down and tap on back tap.
Back Tap Actions
You can even set actions for triple tap as well.
Here's how you can double tap on back of your iPhone to open control center.