Need to force a misbehaving app to quit on your iPhone, iPad or iPod touch? You can do that in iOS 7 using the list of currently running apps.
Need to force-quit an app that is having issues?
Start by double-pressing the Home button at the bottom of your device.
This brings up the list of currently running apps.
Swipe left or right to get to the app you wish to quit.
Now, tap the center of the screen and swipe up.
The app is removed from the list and is no longer running in the background.
You can also force-quit the app you are currently using by holding down the wake/sleep button for three seconds. Then, when the “slide to power off” message appears, press and hold the Home button for about six seconds instead. Some apps will quit and restart, while others will simply quit.