i cannot find the apple app on my tv apps

On what model device is this happening?

List of Apple TV app-supported devices - Apple

The models devices from third party manufacturers on this list support the Apple TV app. Other models devices would not support this app.

Unsupported smart TVs can connect a HDMI streaming device to add apps that way. That can be an Apple TV box, a Roku, a Fire TV, or select game console.

Watch on Apple TV (4K, HD, and 3rd generation) - Apple Support

the 1g and 2g appletv does have the appletv app

you likely has to be connected to a network before it shows up