Drake traded with the Portuguese in Brazil to obtain fresh supplies. Brazil was a Portuguese colony at the time, and the Portuguese were the primary European power in the region. Drake likely traded for items such as food, water, and other provisions necessary for his voyage.
Related Q&A:
Who in Brazil did Drake trade with to get fresh supplies?-Well, I really have no clue who Drake traded with in Brazil to get those fresh supplies. It could have been local farmers, maybe some merchants in the markets, or perhaps some specialized suppliers. But without more specific information, it's hard to say for sure. It might have been a bunch of different people depending on what kind of supplies he was after. Oh man, this is quite a mystery!