The Brazilian government provides a well-organized, multilingual webpage (available in English, Spanish, and Portuguese) with comprehensive information about visas for foreign visitors:
https://www.gov.br/mre/pt-br/assuntos/portal-consular/vistos/informacoes...
There, you will find useful information on topics such as:
- Do you need a visa?
- Where to apply for a visa?
- Visit Visa
- Mercosur citizens
- Visa for minors
- Invitation letter for foreigners

Additional information for US passport holders:
https://www.gov.br/mre/pt-br/consulado-miami/information-about-visas-in-...

For information on obtaining a conference supporting document for your visa application, please contact the FGV-EMAp staff:
Thais da Silva <thais.mancilio@fgv.br>  and  Roseni de Souza <roseni.souza@fgv.br>
(include the following information: full name, institution, passport number, nationality, and a scanned copy of your passport).