I don't know which form I should use between 1040 or 1040NR
Hello,
I have F 1 visa and I have been living in the US over 9 years. I pass the substantial presence test. I submit 8843 each year. I applied for green card lotto last November. Last year, I am working as an OPT for 6 months. So, now I am not sure which form I should use. And what is different between 1040 and 1040NR? Any benefit different? I also need to file a form to refund Medicare and Social Security Tax the my company withhold from each paycheck.
Please help me,
Thank you,
Mew