고마워(gomawo) is used between friends or to a younger person than you. 고마워요(gomawoyo) can be used to everyone in a friendlier way. This is more respectful than 고마워. 고맙습니다(gomapseumnida) can be used to everyone, and it makes you sound more polite and respectuful. 감사합니다(kamsahamnida) is used for a more formal occasion than 고맙습니다.

gomawa should be gomawo and is casual/intimate politeness level, for friends you know well, children etc. kamsahamnida is formal/standard politeness level