If you are a foreign-born person who has married a U.S. citizen, and you are currently staying or living in the U.S., your marriage might qualify you for a green card (U.S. lawful permanent residence), and to apply for it through a process known as adjustment of status (AOS).
First, however, you need to make sure that you are eligible for a marriage-based green card, and eligible to apply for it by adjusting status. If so, we'll give you some helpful information on how to prepare your marriage-based application.
Marriage to a U.S. citizen makes you what is known as an "immediate relative," eligible for a U.S. green card just as soon as you can get through the application process.
Contrast this to the situation faced by "preference relatives," who face numerical limits on the green cards given out annually, and therefore waits of many years after their spouse begins the immigration process before they can move forward and apply for the green card based on their "priority date."
At the most basic, being eligible requires that your marriage is legally valid in the place you were married. For example, some U.S. states prohibit marriages between people who are minors, or those closely related by blood.
It also assumes that your marriage is "bona fide," that is, not just a sham to get a U.S. green card.
Good news if you overstayed a U.S. visa: While people in most visa categories who have done this are not all eligible to adjust status (and must instead apply for their visa through consular processing, in their home country), your marriage to a U.S. citizen basically cancels out the overstay issue, and you can apply to adjust status no matter how long you were out of status.
In fact, you'll be getting a double benefit by doing so, because if you instead chose to apply through consular processing, and your period of unlawful presence in the U.S. was 180 days or more, you'd be inadmissible for some years. In other words, you wouldn't be allowed to return to the U.S. for three years if your unlawful stay was over 180 days but less than a year; and you wouldn't be allowed to return to the U.S. for ten years if your unlawful stay was over a year long.
Important caution: If you used a visa to come to the U.S. with the intention of applying for a marriage-based green card after getting here, you have committed visa fraud, and may be denied the green card on that basis. It's far less likely to be a problem if you weren't yet married when you entered the U.S. and only met your spouse afterward, or decided to get married at least 90 days after your entry.
The news on eligibility to adjust status isn't so good for people who entered the U.S. without inspection, for example by making their way across the border alone. They are not eligible to adjust status unless they happen to fall under old sections of U.S. immigration law (it's unlikely; see an attorney). They will have to apply for their green card through consular processing and possibly face (or request a waiver of) the three- and ten-year bars described above. See an attorney if you are in this situation.
In order to adjust status, you must fill out USCIS Form I-485, along with supporting forms and documents. This form is issued by U.S. Citizenship and Immigration Services, or USCIS. Follow the instructions about What You Need to File I-485 for Adjustment of Status.
You'll see that one of the things you must include with Form I-485 is proof that you are eligible for a green card. In your case, that means proving that you are married, and that your spouse wishes to petition for you. You might have already taken care of both things, if your spouse already submitted Form I-130, Petition for Alien Relative, to USCIS (with a marriage certificate) and received an approval notice.
But don't worry if you haven't already done this: You can submit Form I-130, as well as the marriage certificate and appropriate fee, to USCIS at the same time that you submit the rest of your adjustment of status paperwork.
Also note that, because this is a family-based immigration case, the U.S. citizen spouse will need to file the Affidavit of Support on Form I-864 for the immigrant. The purpose is to show that the U.S. spouse will support the immigrant financially for approximately ten years into the future, thus avoiding the immigrant having to rely on need-based public assistance (often called welfare).
Unfortunately, immigrants can be deemed likely public charges even if the I-864 shows sufficient income. Under Trump-era new regulations, immigrants must provide financial and personal information, including a history of any receipt of public benefits, using Form N-944, the Declaration of Self-Sufficiency. They'll need to attach documentation backing up their statements, too. USCIS will review the "totality" of the immigrant's circumstances in deciding whether the person is inadmissible as a public charge.
The immigrant will also need to undergo a medical exam with a USCIS-approved physician, and include the results with the AOS paperwork. This is related to the medical ground of inadmissibility. Only a limited list of illnesses are a problem.
After your application is processed by USCIS and the immigrating spouse has attended a fingerprinting appointment, you will both have to attend an AOS interview. You can, if you wish, hire an attorney to represent you during this interview.
USCIS will send instructions on what to bring to the adjustment interview. Be sure to bring a well-chosen selection of documents (copies and originals) proving that your marriage is the real thing and that you are sharing a life together. For example, joint bank statements, a mortgage or apartment lease in both your names, evidence of shared health and other insurance, wedding photos, and children's birth certificates are all good forms of evidence.
The USCIS officer will ask about basic information in your application, and ask various questions about your marriage. See What Happens at The Green Card Marriage Interview? for sample questions and other tips on preparing.