How do I discover what app or device was using my camera and microphone

There is no history or a log available to review apps using your camera or a microphone. Below is what is available:

If you see an Orange dot (Microphone) or a Green Dot (Camera) then you know that your Microphone or your Camera is being used by an App. You will see this when you are talking on your phone as well. To check to see which app is actively using the camera or your microphone, you can PULL DOWN on your screen from the TOP RIGHT corner revealing CONTROL CENTER. You will see, at the top, the usage information. This is a live feature and the result will only appear temporarily after the app has been terminated/closed.

Axel F.

Force close apps one by one.