IDOC Financial Aid for MIT

I am applying for financial aid at MIT and now I need to submit my documents to the IDOC. We do not file for taxes in my country, so I need to submit letters from my parents’ employers stating their annual salaries instead of the tax returns. Does anyone know if the letters should be uploaded to the IDOC as well? Or should they be emailed? I know I should email MIT about this, but they never respond to my emails lol. So, anyone?