Multitasking was introduced in iOS 9, allowing you to use multiple apps at once on an iPad. There are three different types of multitasking—Slide-Over, Split View, and Picture in Picture—and they are all on by default.
The Slide-Over feature allows you to interact with a second app in a pane on the right side of the screen (in portrait or landscape mode) and the Split View feature allows you to drag the divider between the apps and interact with both apps (only on newer iPads, such as the iPad Pro and iPad Mini 4, in landscape mode). The Picture in Picture feature allows you to watch a video in a small thumbnail window over other apps, following you as you run different apps. The Slide-Over feature might get in the way in some apps that provide access to features with sliding motions. The Picture in Picture is activated by pressing the Home button while a video is playing. If you find that these multitasking features get in the way more often than they are useful for you, or you just don’t use them. you can disable them.
To disable these three features, tap the “Settings” icon on your Home screen.
On the Settings screen, tap “General” and then tap “Multitasking”.
The Allow Multiple Apps setting enables and disables both the Slide-Over and the Split View features. So, if you have to turn both either on or off. The Persistent Video Overlay controls the Picture in Picture feature. The slider buttons are green if these features are enabled.
To disable these features, tap the slider button so it turned white.
If you decide you want these features on, you can easily turn on these Multitasking settings to re-enable the features. Simply make sure the slider button is green for the feature you want to enable.