Do I have to pay for Apple TV on my smart TV.

If you already have Apple TV+ on your iPhone, then you can use that same subscription on your smart TV. Just sign in to the Apple TV app with your Apple ID account. The subscription is for an account, and the service is then available on any of your devices that has the Apple TV app.

Get the Apple TV app or Apple TV+ app on your smart TV, streaming device, or game console - Apple Support

List of Apple TV app-supported smart TVs and third party streaming devices - Apple

All the ways to watch Apple TV+ - Apple Support

Yes, if you subscribe to tv+ (Apple originals) or any other paid services

tv+ is a monthly subscription.

Read here => Apple TV+ - Apple