U.S. immigration law allows U.S. citizens and legal permanent residents (i.e. green card holders) to sponsor certain family members for green cards. U.S. citizens can sponsor their spouses, unmarried children under 21 years of age and their parents (if the U.S. citizen is at least 21 years old) as immediate relatives. This means that a green card is always available to these applicants. U.S. citizens can also sponsor their unmarried and married children who are 21 and older and their brothers and sisters under preference categories. Legal permanent residents can sponsor their spouses, minor children, and adult children (21 and older, married and unmarried) under preference categories. This means there can be a wait (and sometimes a very long wait) for a green card to become available.
For any family-based petition, whether it is for an immediate relative or in a preference category, the sponsor will need to sign an Affidavit of Support. The Affidavit of Support is filed on Form I-864 and it is a contract between the sponsoring relative and the U.S. government, where the relative attests that they have sufficient income and/or assets to support the person they are sponsoring for the green card. This is an important part of the green card application and is necessary to demonstrate that the applicant will not become a public charge in the U.S.
