Zoom is now freely available on Quest headsets, through an official 2D Android app on the Meta Horizon Store.
It was already possible to join paid Zoom Pro meetings from VR using Meta Horizon Workrooms. Zoom users on 2D platforms see the Horizon Workrooms virtual meeting room as another video attendee, as they would a webcam placed in a real world conference room. It was essentially the Workroom joining the Zoom call, not individual VR users.
Now, the regular Zoom Android app is available on the Meta Horizon Store. It can be used to join any Zoom meeting, free or paid, and as a 2D app it can be used with passthrough as a background, or your virtual home.

Zoom on Quest leverages the feature Meta added to Horizon OS in v76, which gives any Android app requesting the selfie camera a virtual webcam view of your Meta Avatar. That's how you'll appear in meetings if you enable your webcam. On Quest Pro, the face and eyes are driven by face and eye tracking.
Zoom Workplace is available on Quest 3, Quest 3S, Quest Pro, and Quest 2 for free on the Meta Horizon Store.