Marriage to a U.S. Citizen - Green Card Options
Individuals engaged to, or married to a U.S. citizen generally have 4 options to pursue U.S. permanent residence (i.e. a green card).
Option 1: Process From Within the U.S. - Adjustment of Status (AOS):
Individuals currently working in the U.S., e.g. under a TN visa, O-1 visa, etc., who are married to a U.S. citizen may file for a green card by applying for Adjustment of Status (AOS).
The whole process (I-130 petition and I-485 adjustment application) is completed from within the U.S.
All paperwork filed at the same time.
Generally, the fastest of the options. Processing varies based on U.S. location.
May maintain work visa (e.g. TN, O-1, etc.) visa status during process, but depending on the visa type may not be able to renew or obtain a new visa. This could result in a gap in visa status or work authorization based on timing.
Unless possessing H-1B or L-1 visa will face travel restriction until advance parole travel authorization issued.
See more on TN Visa, Marriage to USC & AOS
Option 2: Process From Outside the U.S. - Immigrant Visa Processing (IVP):
Although most often used by individuals married to a U.S. citizen and who reside outside the U.S., immigrant visa processing (IVP) may also be used by individuals working in the U.S. under a temporary worker visa.
IVP involves a two stage process: (1) filing of the I-130 petition; and (2) applying for immigrant visa at U.S. consulate.
IVP does not provide any authorization to reside or work in the U.S. until the immigrant visa is issued. Individuals must rely on a temporary worker visa (e.g. TN, O-1 or other visa) for the interim.
Travel on, or renewal of temporary visas like TN visas is possible, but may be scrutinized during IVP.
Options 3 & 4: K-1 or K-3 Visa:
AThe K-1 visa (engaged to a U.S. citizen) and K-3 visa (married to a U.S. citizen) are generally used by individuals who reside outside of the U.S.
The K-1 visa is a three stage process: (1) filing of I-129F petition; (2) applying for K-1 visa at U.S. consulate; and (3) entering the U.S. and applying for Adjustment of Status.
The K-3 visa is a four stage process: (1) filing of I-130 petition; (2) filing of I-129F petition; (3) applying for K-3 visa at U.S. consulate; and (4) entering the U.S. and applying for Adjustment of Status. (The K-3 is often converted to IVP when the I-130 is approved before the I-129F.)
For individuals already working in the U.S. under valid visas, the K-1 and K-3 is generally of little benefit.