Is there way to crop the output of a camera for a video chat?
Cameras either have or don't have these features.

Pan (side to side adjustment),
Tilt (crop &amp; enlarge),
or Zoom (up &amp; down adjustment)

This is shown as P/T/Z or PTZ on feature lists.
Apple's built in FaceTime camera has none of these sadly, you will have to look at the specs for any external camera you have to see if it does.
While there is some 3rd party apps that apply these after the fact, they do it by taking the video feed, adjusting it and pushing out a new virtual feed.
Since these will likely be suggested, be aware, these can be problematic. They can be buggy, they often ask for very deep control/access of your system, and some programs do not take virtual video input well. This is reflected in their universally poor ratings in the App Store. I have also found they are stubborn to uninstall and run insidiously in the background, so use at your own risk.