Consular processing generally refers to obtaining immigrant and non-immigrant visas in posts (embassies and consulates) of the Department of State throughout the world. Foreign nationals may obtain non-immigrant visas to enter the United States temporarily. Consul officials also have the authority to grant immigrant visas, with which foreign nationals enter the United States with the intent to remain permanently as legal permanent residents. Once the immigrants arrive, the processing is completed in the United States and the green cards usually arrive in the mail.
Spouses of U.S. citizens who live abroad are a special category. They also undergo consular processing for K-3 visas, which demonstrate an immigrant intent. However, K-3 visa holders must apply for legal permanent residency after they enter the United States.