Use the built-in camera on Mac
Many Mac computers and displays have a built-in iSight, FaceTime, or FaceTime HD camera located near the top edge of the screen. The camera automatically turns on when you open an app that can take pictures, record videos, or make video calls.
Turn the camera on: On your Mac, open an app that can use the camera, such as FaceTime, Messages, or Photo Booth. A green light beside the camera glows to indicate that the camera is on.
Turn the camera off: On your Mac, close or quit all apps that can use the camera. The green light beside the camera turns off, showing that the camera is off.