A:AnswerReally, any webcam that plugs into a USB port will work. The one that works 'best" for you depends on what you need it to do (low light, wide field of view, etc.) and what your budget is.
A:AnswerThere are a variety of microphones available today for computers. You can use a basic microphone that plugs into the computer using the USB cable. Or there are more advanced microphones available that have bidirectional or omnidirectional capabilities. They also can pick up your voice and isolate from other signals. Some microphones are considered to be "hot", otherwise known as condenser microphones. I would recommend doing some research on microphones for computers to find the best one for you. Or if a store is open near you, I would recommend reaching out to a blue shirt at Best Buy.
A:AnswerDesktops generally do not come with built-in mics or cameras. You can purchase a very good usb webcam for under $50. Just plug it in and place on your monitor.
A:AnswerI have my hp connected to a 50” uhd via a hdmi cable. I would check my connections and if you can swap monitors to test before making any new purchases.