1. Formal way - Kamsahamnida
2. Informal yet polite way - Kumayo
3. Informal way - Kumawo

here are some other words of thank you in Korean Formal way - Kamsahamnida Less Formal - Komapsuemnida Informal way - Kumawo Informal yet polite way - Kumayo *here's a tip for those who really wants to learn korean easily* -when you see a word that ends in (-yo) its in a polit way.. -when you see a word that ends in (-imnikka) its a more formal way.. -when you see a word that ends in (-imnida) its a formal way.. -and if you see a word that ends without -yo or -imnida it's the original word or a present word..