Was an article a few weeks ago about this, extremely hard for a Mac to have camera on and the USER not knowing... see that little green led next to camera? yep, hardwired to the camera.
They say it's possible... but more likely to have the camera stream hijacked. (you have the camera on legitimately talking with someone, and the stream is compromised)
Beyond that malware specifically targeting the Mac is rare. If we are talking windows... place tape over the camera.

For mac, you can place tape over if you like..
Best thing you can do, don't install ANY software unless you are certain of it's origin. (respected company)
Including browser extensions...
If you think you have some malware installed somehow, run some Mac antivirus. Has to be something like malwarebytes for mac right? I've never looked tbh.