'Obrigada' is the feminine form of 'obrigado'. So if a man wanna say thank you, he uses 'obrigado' and the woman should use 'obrigada'. I'm not sure if it is what you want to know, hope so.

Man says 'ObrigadO' (Thanks). Woman says 'ObrigadA' (Thanks).

Obrigada is for woman, Obrigado is for man :)

obrigado for men and obrigada for women!

Obrigado é utilizado por homens (o).E obrigada pelas mulheres. The word "obrigado" is used for man and "obrigada" for women.