A person applies for U.S. citizenship through U.S. Citizenship and Immigration Services by meeting the eligibility requirements. He must fill out and send Form N-400 Application for Naturalization along with necessary documentation, reports USCIS. After the application processes, he must go for a biometrics appointment and an interview.
An individual applying for U.S. citizenship must be at least 18 years old; of good moral character; a resident in his state or district for at least three months; and a resident of the United States for at least five years, according to Nolo. He must know the English language, be able to pass a U.S history exam, swear that he believes in the ideals of the U.S. Constitution and affirm loyalty to the United States.
Along with Form N-400, applicants must send two passport-size color photos and all necessary documents listed on the USCIS document checklist, states USCIS. Processing of Form N-400 typically takes several months, after which applicants receive notice of the details for their fingerprinting and interview appointments, reports Nolo.
Once the entire application procedure completes, USCIS sends a written notice that either confirms naturalization, that the application remains ongoing due to missing documentation, that the applicant has failed to pass the history or language exam, or a denial of naturalization. If the USCIS grants citizenship, applicants attend a ceremony during which they take an oath of allegiance to the United States.