Online drum lessons work by letting you join a live and private meeting on a video-chat app. You need a place with fast Internet, lots of light, an adjustable camera, a microphone, and a quiet room where no one will distract you.
The teacher will correct your posture and technique while watching you play. However, the tutor may also ask you to record your practice sessions and send those videos to them for closer review so that they can give more in-depth feedback too.