I know that I can cover a webcam with tape, but what can I do to block a microphone embedded in a webcam? Will tape be sufficient to block sound to the microphone, or will I need to do something else?
While there will always be doubt about whether the mic will still record something that will be analyzed through signal processing to determine what were the sounds that produced a certain recording, I'd go the other way around: create significant noise to disrupt any coherent or analyzable signal of the recording
I usually achieve this by simply placing the web camera's embedded mic slot in the path of the computer case's ventilator exhaust, or having it touch the noisy frame of my rig.
The noise will mask effectively any worthwhile sound that may be recorded, such as casual conversation, and will yield any subtle signals useless, such as keystroke micro echos that could be analyzed for timing and intensity to determine a password based on such recordings.
Just attach one of the leads to a little sliding switch. It takes a moment to drill and cut. The computer won't care, the mic is an analogue device, usually.
If you want to disable it, use a tiny flathead screwdriver to scrape out the tiny mic. Alternatively, take a small drill (1mm, not a powerdrill) and drill into the small plate. It won't vibrate very well after such surgery.
Personally I love it when people listen to me, so usually I don't tinker with it.