The correct way of saying what are you doing in Korean is...?
When I try to look this up, I literally get 9 versions excluding the super-formal Google Translate version.
너는 무 엇을 하고있니?
ㅈ금 뭐 하니?
I understand some of these are just varying versions of formality, but I don't understand where all the different phrases come from or in what situation to use them since they seem to have different meanings.