If you marry a U.S. citizen, you may be able to apply for a green card even if you entered the U.S. without a visa, depending on your location and court decisions.

If you marry a lawful permanent resident, you typically must have entered the U.S. lawfully (with inspection) to adjust status inside the U.S. under most circumstances.

If you travel on Advance Parole and reenter the U.S., that counts as a lawful entry, which can make you eligible to adjust status after marriage to a citizen.

You’ll need to file Form I-130 (Petition for Alien Relative) and Form I-485 (Application to Register Permanent Residence or Adjust Status).