Just genuinely wondering but if i was to KO somebody where is the best place to hit them? :)?

yeah so im just wondering because i like to learn these kinda things, i would do it to someone im not that kinda person but if i was where? im 14years old and weight 8 stone and am 5'7 and average strengh for my height. Im only telling you that info because i was thinking if i was older and stronger mabye hitting them in a different place would be more effective :)