How to enable iPhone's secret double-tap shortcut

The Back Tap feature, introduced in iOS 14, lets you perform actions on your iPhone by double- or triple-tapping the back of the device — without any on-screen gestures. It's hidden in the accessibility settings, but once enabled, it simplifies everyday tasks, from taking screenshots to launching shortcuts.

SlashGear writes about it.

How to enable and configure double tap

Open Settings > Accessibility > Touch > Back Tap and scroll down to Back Tap. Once you’ve selected Double Tap, assign it to take a screenshot, lock the screen, mute the sound, enable Live Captions, or launch a custom shortcut. You can also enable Triple Tap for the second command.

Once set up, tap the top or center of the case fairly quickly and clearly — the motion sensors detect the gesture even under most cases, so you don’t have to take them off. The rhythm is easy to learn: a few tries and the gesture becomes intuitive. You can return to the Back Tap menu at any time to change or disable the assigned actions.

If the system doesn't respond, check that your iPhone 8 or later is running iOS 14 or later — older models won't have this option. Thick shockproof cases sometimes block the sensors, so remove them to test. The double tap should be short, but sufficiently noticeable. If necessary, restart your smartphone — sometimes this solves the problem.

As a reminder, more than 18 years have passed since the first iPhone, and each new model is not without small technical nuances. Sometimes even the latest Apple smartphone starts to slow down, but a simple reboot often solves the problem.