There are a few 3tdpary add-ons if the onboard cams are not providing the xp your looking for. Which headset are you referring to?
If it is Dream Air Lighthouse models then you need a 3rdparty option.
- Zed mini (likely pretty expensive)
- MRGO uses web cam and is available on steam.
- Pass through Forge dev working on an option for headsets like Pimax.
Use the search function.
@ludiks made this as well that uses I believe webxr? And can also use a webcam.