Back Tap

The iPhone has a limited number of physical buttons. Except for the Action button, you can’t customize them to perform different actions.

Fortunately, there’s an accessibility feature called Back Tap, which lets you effectively add two extra buttons to the back of your iPhone. With Back Tap turned on, you can tap the back of your iPhone twice or thrice, triggering a specific action you set beforehand. 

For instance, you can open Control Center or activate Siri. There are many options, and here’s how to set them up:

1. Open the Settings app.
2. Scroll down and tap on Accessibility.
3. Under Physical and Motor, tap on Touch.
4. Scroll to the bottom and select Back Tap.
5. Tap Double Tap or Triple Tap, and choose the action you want your iPhone to perform when you trigger these gestures.

And that’s it! After selecting the action, you can tap your iPhone twice or thrice to see how well it works. Keep in mind that this will only work with iPhones with Face ID. Moreover, how well this feature works will depend on whether or not you’re using a case and how thick it is. So, you might need to give it a hard tap for your iPhone to register it.