Exposé
Exposé is a display of all your open apps and windows.
To open Exposé, do any of the following:
Swipe up from the bottom edge and pause in the center of the screen.
Double-click the Home button (on an iPad with a Home button).
To see more apps, swipe right. To switch to another app, tap it. To close Exposé, tap the screen or press the Home button (on an iPad with a Home button).