I did a internship during one year (2011), who was paid (1'500$ a month). When I arrived in the US, I thought I was on a payroll system with my company but it appeared they were considering me as a freelancer. My exchange company advised me in April that I had to fill a tax return form, but I felt not concerned as someone told me I have to pay some taxes later on by myself. I ended my internship 2 months ago, and I am back in my country, but i wanna fill my taxes form. Which form do I need to fill, the W9 form? it says it is only for us persons...I'm not even sure now the company I worked for was allowed to consider me as a freelancer.
Also, I have a pending application for a O1 visa at the USCIS right now.
Could someone advise me please on this case? Do someone knows what is the percentage of the income made in 2011 that I will have to pay?