Form I-485 is one of the most important immigration forms in the United States.If you are applying for a marriage-based green card through Adjustment of Status (AOS), this application determines whether you will become a permanent resident without leaving the country. USCIS reviews this form carefully, and even small mistakes can lead to delays, RFEs, or denials. In this guide, I will break down everything you need to know about how to file Form I-485, how the process works