How can cast Apple TV to main tv

The standard method for streaming from iPhone is AirPlay. Apple’s own apps would support AirPlay.

Use AirPlay to stream video or mirror the screen of your device - Apple Support

If AirPlay or screen mirroring isn’t working on your device - Apple Support

AirPlay system requirements - Apple Support

AirPlay streaming requires an AirPlay-receiving device. This can be an Apple TV box, or an AirPlay-enabled smart TV, or modern Roku. List of AirPlay 2-enabled smart TVs - Apple

Also see: All the ways to watch in the Apple TV app - Apple Support

for non-casting solutions.

apple use their std. called airplay the tv has to support that

Apple TV app - Devices - Apple

AirPlay 2–Enabled TVs and Devices