i can t see tv app

If you have an

Apple TV HD, tvOS 14

then its home screen would look something like this (the background image may be different):

The black icon on the left with “tv” on it is the Apple TV app.

If you do not see an image from the Apple TV box on your TV screen, then see: If your Apple TV doesn't turn on - Apple Support

If you have no Apple TV box, then what other supported device do you have? Apple TV app - Devices - Apple

iPhone 6

That is important to know.

iPhone 6 should be updatable to iOS 12.5.1. Update your iPhone - Apple Support

Devices with iOS 12.3 or later should have the re-designed TV app.

The blue tint was changed to white in later versions iOS.

If removed, it can be re-downloaded from the App Store.

Can you see the Apple TV home screen, with all the icons for various services?

Unless you moved the app icon, the TV app would be in the top row on the left side.

If removed, the TV app can be re-downloaded from the App Store.