Hello, Natalia. Nice to meet you. First of all, let me break down the structure of each phrase below; A. ありがとうございませ -> ありがとうございます 　=　ありがとう + ございます "Thank you" B. どもありがとう -> どうもありがとう 　=　どうも + ありがとう "Thanks a lot" Basically the difference between those two are 1) the level of politeness and 2) the level of gratitude. 1) the level of politeness: A > B The phrase A contains ございます, which shows your respect to who you are talking to, while the other does not. Therefore, A is polite, but B is not. 2) the level of gratitude: A < B The phrase B has どうも, which means "a lot/very much", but the other does not. So the phrase B represents deeper gratitude than A. In conclusion; ・ありがとうございます is polite enough to say to those who you need to behave: teachers, elders, people at first site, your boss, etc. However, you can't tell how appreciated you are from the text itself. ・どうもありがとう shows a lot of gratitude, but kinda casual that you better say it only to your friends. Hope this help you. FYI, you can also say どうもありがとうございます as the combination of both :)

Thankyou :)

The 1st is ありがとうございます The 2nd is どうもありがとう In my opinion: When talking with stranger or a person of figure, choose the 1ST When talking with friends, choose the 2ND