Apple just introduced a new feature and it is the Slide-over. Slide-over is a new feature you’ll find on your iPad when you upgrade to iOS 9. It is a bid to increase the multitasking capabilities of its tablet lineup.
Accessing slide-over is very easy; when making use of an app, slide your finger in from the right edge of your iPad’s screen. A small panel will slide out along with your finger, showing a column of app icon. In this process, an app is already open, you can slide your finger down from the top of the slide-over panel to bring up the list of apps.
Tap the one icon you want to launch in slide-over. Notice you can then use the app as you would if you were using the app in fullscreen mode. When you are done, slide the left-edge of the slide-over panel to the right to close.