Triple-click Home provides an easy way to turn some of the Accessibility features on or off when you press the Home
button quickly three times. You can set Triple-click Home to turn VoiceOver on or off, turn White on Black on or off, or present the options to:
Turn VoiceOver on or off
Turn Zoom on or off
Turn White on Black on or off
Triple-click Home is turned off by default.
In Settings, choose General > Accessibility > Triple-click Home and choose the function you want.