Sometime after you've filed your application for a green card based on your marriage to a United States citizen, you'll have to face the "marriage interview." This is where you have to provide enough evidence to satisfy the interviewer that your marriage is real, not a sham designed to get around immigration laws.
A lot of couples face this with some anxiety because they're uncertain what types of questions they'll be asked. In reality, you'll most likely only have a brief interview, unless the examiner suspects a problem.
You can help yourself avoid raising suspicions about the legitimacy of your marriage by taking original documents with you that lend weight to the marriage's validity. Make a copy of all of these documents in order to give them to the immigration examiner for your file.
Some of the best documents you can use to show the validity of your marriage may actually predate the day you said your vows -- simply because they show that there was an actual relationship between you and your spouse that naturally evolved into a marriage.
Try to bring as many of the following documents (and copies) with you as you can:
-- Photographs of you and your spouse both prior to your marriage, during the wedding, and after the marriage are helpful. If your relatives and friends are in some of the photos, that's even better -- it shows that you aren't trying to keep the marriage a secret.
-- Letters, cards, and other correspondence between you and your spouse, including email. If your marriage was arranged according to your religious customs, the correspondence between your family members making the arrangements helps establish the validity of the relationship.
-- Rent or mortgage documents in both your names, joint credit card accounts, joint bank accounts, and other evidence that you and your spouse have joint finances.
-- Wills, powers of attorney, and other documents that show you are planning on being married for a long time. Documents showing that you've named your spouse as your beneficiary on any pension plans or insurance benefits.
Preparing for the interview doesn't have to be stressful. You might consider hiring an attorney with experience in family law to help you gather the right documents and prepare others, like an updated will and power of attorney.
Source: FindLaw, "What documents are necessary to determine a bona fide marriage?," accessed March 30, 2017