We use single and double clicks on our iPhones and iPads to return to the Home screen and open the app switcher. Apple also offers an accessibility option that lets you enable and customize a triple-click. You can choose between a few options so you can pick the one that's most convenient and useful for you.
How to enable and use the triple-click Home button shortcut on iPhone and iPad
Launch the Settings app on your iPhone or iPad.
Tap on General.
Tap on Accessibility.
Tap on Accessibility Shortcut — it's all the way at the bottom.
Choose the action you'd like to perform when you triple-click the Home button.
Here's a brief description of the options you have and what they are:
VoiceOver - Allows your iPhone or iPad to speak to you when enabled. Commonly used by folks with visual impairments.
Invert Colors - A great option for anyone with a visual impairment such as color blindness. All colors across iOS will be inverted.
Zoom - Allows you to zoom the Home screen and all other content for better visibility. You can then use two and three finger gestures to tap and pan around.
Switch Control - Lets you use external switches, or the screen itself, as a switch for motor accessibility.
AssistiveTouch - Adds the ability to access many common hardware buttons and gesture controls with single taps. A useful feature for those with motor impairments.
Once you've made your selection, simply triple-click the Home button from anywhere and your iPhone or iPad will enable the function you've selected. Triple-click it again to disable it. If you've assigned a triple-click function, what one do you use?