When you like something, you can use both 좋아요 and 좋아해요.
But the fundamental difference is that 좋아요 originally means that “something is good or likable” whereas 좋아해요 means that “YOU like it” – So when something sounds good and you like the idea, you can say 좋아요. But when you want to talk about you liking something actively, you can say 좋아해요, meaning that you like it. So for example, if you like a certain K-Pop band, you can say the name of the band and then add 좋아요. It means they are likable and good. If you say 좋아해요, it means you are fond of them and you like them.
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