Hello, justvictor.
To start us off, please take a look at the steps in this article that explain how to use AirPlay on your Mac: Stream audio and video from your Mac with AirPlay - Apple Support. As you can see in the steps, the options you have to share depend on the type of content you want to share.
For streaming to an HDTV specifically, check: Use AirPlay to stream what’s on your Mac to an HDTV - Apple Support.
- "Make sure your Mac and Apple TV are on the same network.
- Click the Screen Mirroring icon in the Control Center, then choose your Apple TV.
- To set whether your desktop matches the size of the Mac screen or the TV screen, click the AirPlay status icon then choose This Mac or your Apple TV. When you’re using AirPlay Mirroring, the AirPlay status icon in the menu bar is blue."
Let us know if we can help with anything else at all or if this doesn't settle your issue. Thanks and have a fabulous day!