iOS is the operating system software installed on your iPhone. To find out which version you have: Tap Settings, Tap General, Tap About, and view the version number.
Some applications aren't ended completely when your mobile phone returns to standby mode. They keep running in the background unless you end them from the list of active applications.
Tap the Home key twice. At the bottom of the display a list of active applications is displayed.
Tap and hold any menu item until the menu items start to jiggle.
Tap - in the top left corner of the required menu item to end the application.
