I am a Colombian citizen with a Colombian passport and a US tourist visa. I will be in the USA for a couple weeks and then travel straight from there to Brasil, and then straight from Brasil to Canada. Can i apply for a Canadian tourist visa from the US? And if I were to need any additional permits to enter Brasil, could I get them from the US too? Would any Brasil and Canada embassies in the US be able to help me with that? Thanks a lot!
A citizen of Colombia does not need a visa to enter Brazil for a visit of up to 90 days. You can just show up and present your passport or Cédula de Ciudadanía (ID card).
You do need a visa to visit Canada though. You are allowed to apply for it from within the United States, but since it may take several weeks to process, you probably do not have enough time to receive it. If possible you should apply for the Canada visa before you leave Colombia. At the time of writing, the processing time for applications made in the USA is 42 days, and from Colombia is 16 days.