Apple TV Icon not on Samsung Smart TV

if it's not preinstalled and not in the samsung app store on the tv then maybe the tv model does not support the app in which case you can read

How to watch Apple TV+, MLS Season Pass, and more - Apple Support

See the following from Samsung https://www.samsung.com/us/support/answer/ANS00082624/

You do not even need to download it because it will appear in the Apps section on your device.

Note: If the Apple TV or Apple Music app does not appear in apps, then it is not compatible with your TV.

If your Samsung isn't compatible, another option is to use a 3rd party device such as Roku. I do that with my LG TV even though it is compatible.

Another device is the following from Apple: Apple TV 4K - Apple