Is the teeth whitening effect good?

I'm in my 30s considering teeth whitening. I'm not extremely yellow, but since I drink a lot of coffee, my teeth have become a bit yellow. That's why people suggest using a straw when drinking coffee, but I usually don't use a straw for hot coffee, except for iced coffee.ㅠㅠ

So I want to whiten my skin, but I'm really curious about how the process works, whether it is effective, if I need to do it regularly, and so on.