“Public charge” is a ground of inadmissibility. Grounds of inadmissibility are reasons that a person could be denied a green card, visa, or admission into the United States. In deciding whether to grant some applicants a green card or a visa, an immigration officer must decide whether that person is likely to become dependent on certain government benefits in the future, which would make them a “public charge.” It is not a test that applies to everyone, not even to all those applying for green cards.
The Immigrant Legal Resource Center (ILRC) provides trainings and technical assistance on public charge, produces numerous practice advisories, toolkits, and other resources, and authors a comprehensive manual, Public Charge and Immigration Law.