With SharePlay, you can instantly stream supported content, listen to music, play games, and more in sync with a friend by holding your iPhone close to your friend’s iPhone.
On your iPhone, in an app that supports SharePlay, tap the content you want to share.
Hold your iPhone next to the iPhone of the person you want to share with.
If they’re not in your contacts (or vice versa), you first need to share your contact information with them. See Use FaceTime on Apple TV 4K (2nd generation or later)