FaceTime on MacBook Air running OS 10.13.6 High Sierra

Hello JoanofArc,

Welcome to the Apple Support Communities. I understand some options are missing once setting up a FaceTime call with your Mac. I'll do what I can to help.

If you're wanting to start an invite for Group FaceTime, that would require macOS Mojave or later. Take a look at this link for the options that you can do during a FaceTime call: Use FaceTime on your Mac

If you meant something else or the expected options aren't displaying, try these troubleshooting steps:

• Restart your Mac from the Apple () menu then Restart.
• To narrow it down, also be sure to check your Mac in safe mode: Use safe mode to isolate issues with your Mac You can also try a new user as well: How to test an issue in another user account on your Mac
  • If it only happens in your user and not in safe mode, try removing login items that interact with the camera, microphone, or FaceTime: Open items automatically when you log in on Mac
  • If it happens in both safe mode and a new user, back up your Mac and reinstall macOS using Recovery which will reinstall FaceTime: How to reinstall macOS from macOS Recovery

Best regards.