All companies, foreign and domestic, are required to file annual reports, registration statements, periodic reports, and other forms electronically through EDGAR (the Electronic Data Gathering, Analysis, and Retrieval system).

Anyone can access and download this information for free. Access to a lot of Report Types. Two of the most common are 10-K, which is the annual report of listed companies, and 20-F which is annual report of foreign companies operating in the US. On the SEC homepage there is a list and a description of all the SEC Forms.