Adjustment of status means a process of getting a green card without coming back to the home country for a completion of visa issues. In other words, if you are present in the United States, you can apply for a status of lawful permanent resident and get a green card. To do this, you have to use Application to Register Permanent Residence or Adjust Status, known as Form I-485.
There are different ways to adjust status to a lawful permanent resident, provided by the immigration law and some federal laws. Variable requirements for adjustment of status depend on immigrant category you belong to. Each category has its own criteria. For example, if you are a family member, employee, K-1 visa holder, refugee, parolee from Poland or Hungary, Panama Canal Zone employee or physician, or certain U.S. armed forces member, you must meet those criteria and document them upon Form I-485 submission. Overseas applicants are not eligible to submit Form I-485 and must undergo a “consular processing”. If you live abroad and have an immigrant petition that was approved, you need to apply for an immigrant visa via U.S. consulate in your country.
February 2, 2019