Can someone explain camera drones to me?

I see various advertisements for camera drones of various sizes. It looks like the operator places his/her cell phone (or similar device) into the carrier on the drone and turns it on.

Then the drone is launched and goes on its merry way. And if you’re lucky, makes it back home.

How does this work? Is the camera/phone streaming the whole time? Or is the camera simply taking video and when it lands, the operator uploads the video?

Is there a specialized camera or will any smartphone do? Are the drone carriers strong and secure? Etc.