For anyone confused, there are many ways to say "Thank You" in Korean. "고마워" is casual and should be used with people you are close to. Adding "요" to the end makes it casually polite. "감사합니다" is the most formal way of saying "Thank You" in korean, so normally you'd use this with people of higher status. There are so many more ways, here are just the most common.
Hopefully this post explains the presence of multiple ways to say "thank you" in Korean.
There are two verbs you can use to express thankfulness:
고맙다 and 감사하다
They are both interchangeable, however there is a slight nuance that I must explain.
해체 and 해요체
In casual or polite speech, it is more common to use 고맙다. They are used like this:
In formal speech, people tend to use 감사하다. It is used like this:
She/He is talking about a Live Korean class by Hyunwoo (a TTMIK teacher) in which he said that sometimes Koreans also write 탠규 (taen-kyu) for Thank You, and they don't always use 고마워.
TTMIK is Talk to me in Korean. Its is a great Website for learning Korean, they also have a YouTube channel, with a great content.
Good luck! :)
After watching so many Korean dramas, I noticed that this, "thank you" is spoken between friends - less formal.
No, they're not related.
고마워 is the Korean translation of "thank you".
こんばんは is the Japanese translation of "good evening".