Where to put it, in one paragraph
In front of you, slightly to one side, and above eye level, angled down at your face. That is the whole technique. A light beside your monitor at eye height flattens your face; a light below you produces the campfire-ghost-story look; a light behind you turns you into a silhouette. The most common real-world mistake is a bright window behind the desk — if you cannot move the desk, close the blind and let the lamp do the work, because no webcam wins an argument with daylight.
Distance matters as much as position. A small panel two feet from your face is a soft, flattering source. The same panel across the room is a hard little point of light that carves shadows under your nose. Close and dimmed almost always beats far and bright.
Panel or ring?
An edge-lit panel off to one side gives a slightly dimensional, natural look and keeps your desk clear of a hoop. A ring lightsits around or beside the camera and produces flat, even, shadowless light with a distinctive circular catchlight in the eyes — extremely forgiving, and instantly recognisable as a ring light to anyone who has used one. Neither is wrong. Panels look a little more like a studio; rings are the easier win if you do not want to think about placement at all.
Colour temperature is the other control worth using. Match the light to the room rather than fighting it: warm bulbs around you and a cold blue panel on your face is the combination that makes people look ill on camera. Bi-colour lights let you dial that in, and the picks here that offer it are the ones to prefer if your room lighting changes through the day.
Software control is not a gimmick
The reason streamers pay extra for a software-controlled panel applies just as well to a working day of calls: you adjust brightness and warmth from the computer or phone without reaching behind a hot light between meetings, and the same setting comes back tomorrow. If you take four calls a day, that convenience compounds. If you take one a week, buy the cheaper light and spend the difference on a better webcam.