You may need a visa for Iran if you have a Brazilian passport
Visa options for Iran
Electronic visitor visa is required for trips longer than 15 days
Travelers need an electronic visitor visa for Business or Tourism if they stay in Iran for longer than 15 days. Travelers don’t need a visa to visit Iran for Tourism for a maximum stay of 15 days or less. Travelers may enter Iran every six months and stay 15 days for each entry. The 15-day stay can not be extended; visitors intending to stay longer must apply for a visa.