Turning off your iPhone involves two simple steps. With the touch of a button and a virtual slider, you can shut down your device in a few seconds. If you are having difficulty powering off the device, perform a quick reset to resolve a frozen or unresponsive condition before shutting your iPhone off.
Press and hold the "Sleep/Wake" button on the upper-right edge of your iPhone. A red power-off slider will appear at the top of your screen.
Slide your finger across the slider, from left to right. Your device will then cycle down and shut off.
Reset your iPhone if your iPhone does not shut down. Your device may be hung up on a frozen or corrupt app. Simultaneously press and hold the "Sleep/Wake" button and the "Home" button for roughly ten seconds until the Apple logo appears. Once your Home screen reappears, repeat Steps 1 and 2 to shut down your iPhone.