Apple TV app on iPhone

you click on the appletv app on the iphone it replaced the old video player and will play videos you sync to the iphone

and movies and tv series you can rent and if you have an appletv+ subscription you can watch that streaming service

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Connect apps and add your TV provider to the Apple TV app on iPhone - Apple Support

“No videos”

The TV app on iPhone needs internet access, to show anything other than the local library.

• Through Wi-Fi, the TV app should have regular internet access.
• On cellular, the TV app would need extra permission to use cellular data. Settings﹥Cellular﹥[scroll down to apps list] TV app﹥