can you airplay on the apple tv app

The Apple TV app and AirPlay capability are two independent features. Often seen together, but not necessarily so. One does not require the other.

1. On what device do you have the Apple TV app?
2. AirPlay streaming is from one device to another. With which devices did you intend to use AirPlay?

AirPlay system requirements - Apple Support

List of AirPlay-enabled smart TVs and third party streaming devices - Apple

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