Hi Frank Boateng,
Camera widget cannot be used in web browser which is specifically developed for native mobile apps. If you need to access your camera in web browser there is an alternative way we can use Html snippet there you write a simple HTML code to open camera and using JAVASCRIPT Functions handle the camera open, close and snapping (Mendix supports javascript widgets).
Refer this : https://www.digitalocean.com/community/tutorials/front-and-rear-camera-access-with-javascripts-getusermedia