Picture in Picture (PiP) lets you watch an adjustable thumbnail-size video play in any corner of your screen while you do other things on your phone. The video remains open even while you do other things. For example, you can now watch your favorite Netflix or Amazon Prime show or talk to a friend over FaceTime while simultaneously composing an email or using any other app on your phone.
To enable Picture in Picture, go to Settings > General > Picture in Picture and toggle on.
Picture in Picture is very simple to use; just begin watching a video or start a FaceTime call and then go to your home screen, or click the minimize button. The video or FaceTime window will continue playing, but in a smaller thumbnail view. You can move the thumbnail anywhere on your screen and double-tap to increase its size.