How do I get the AppleTV app on my TV?
How do I install the Apple+TV app on my Samsung TV?
If your TV model is on the list of supported models, then it would either be pre-installed, or downloadable from the TV manufacturer’s on-device App Store.
List of Apple TV app-supported smart TVs and third party streaming devices - Apple
Watch on Samsung Smart TVs - Apple Support
Use apps on your Samsung smart TV - Samsung Support
About the Apple TV app on Samsung TV - Samsung video apps
If your model TV is not supported, then you’ll have to connect a supported streaming device to your TV, in order to access the Apple TV app.