Obrigado(a) é a forma de dizer "thank you", mas essa forma se altera dependendo que quem está falando: Woman (mulher) = Obrigada Men (homem) = Obrigado

Uma boa explicação aqui: https://www.flip.pt/Duvidas-Linguisticas/Duvida-Linguistica/DID/1008

The word "obrigado" is the past participle of the verb "obrigar". The expression "obrigado(a)" is the reduction of phrases used few centuries ago such as "estou obrigado a você". These phrases expresses the recognition of a debt (You've helped me, so i'm obliged to you). Throughout the years, the phrase was reducted to just the past participle of the verb. Since the verb agrees with the subject, if the subject is a masculin noun, the verb assumes the form: obrigado. But if the subject is a feminin noun, the verb agrees: obrigada. Hope this helps.

If you´re going to use "obrigado/a" to express gratitude you should use as follows: - Obrigado. (If you are a man) - Obrigada. (If you are a woman) There are other uses for the word, for example: - Elas foram obrigadas a ir embora. (They were forced to leave) As you can see, in Portuguese, because the word agrees with the gender, you can tell that we're talking about women/girls (they).

Thank you all :) When I was in Portugal, someone told me that you use obrigado or obrigada depending on who you're thanking, so if it's a girl it's with the -a and if it's a man with an -o. That's why I found it confusing :)