Use the built-in camera on Mac
Many Mac computers have a built-in FaceTime or FaceTime HD camera located near the top edge of the display. The camera automatically turns on when you open an app—such as FaceTime or Photo Booth—or use a feature—such as Markup or head pointer—that can use the camera. A green light beside the camera glows to indicate the camera is on. The camera (and the green light) turn off when you close or quit all apps or features that can use the camera.
Control access to the camera
You can decide which apps are allowed to use the camera on your Mac. See Control access to the camera.
Take a photo or record a video
Improve image quality
Clean the camera: Use a soft, lint-free cloth to wipe the camera.
Adjust lighting: Make sure you are well lit from the front, without a lot of light behind you; for example, with windows in front of you.
Improve your Wi-Fi connection: Move closer to your Wi-Fi router and make sure there are no objects impeding its signal, such as walls.
Change app settings: Certain apps may allow you to adjust camera quality. Check your app settings and adjust if needed.
Use your iPhone as a webcam: Connect to a supported iPhone and use its camera instead of the built-in Mac camera. See Use your iPhone as a webcam on your Mac.
Troubleshoot camera problems
See the Apple Support article If your built-in camera isn’t working on your Mac.