To be eligible to complete a U.S. citizenship application, which includes N-400, Application for Naturalization, you must fulfill several requirements.

These requirements include:

• Age: Applicants must be at least 18 when filing the N-400 application.
• Lawful Permanent Resident status: Applicants must have been lawfully admitted to the U. S. for permanent residence and must have held such status for at least five years before applying. For spouses of U.S. citizens, this requirement is reduced to three years if the applicant has been living in a marital union with the same U.S. citizen spouse during such time.
• Continuous residence: Applicants must have continuously resided in the U.S. for at least five years immediately before applying. For spouses of U.S. citizens, this period is reduced to three years. Absences from the U.S. of more than six months but less than one year may disrupt this continuous residence unless the applicant can provide evidence to establish that they did not abandon their permanent resident status.
• Physical presence: Applicants must have been physically present in the United States for at least 30 months out of the five years (or 18 months out of the three years for spouses of U.S. citizens) immediately preceding the application.
• Residence in a particular USCIS district or state: Applicants must have lived for at least three months in the state or USCIS district where the application is filed.
• Good moral character: Applicants must demonstrate good moral character for five years (or three years for spouses of U.S. citizens) before applying and up to the time of naturalization. Certain criminal offenses may impact this requirement.
• English language proficiency: Applicants must demonstrate an understanding of the English language, including an ability to read, write, and speak basic English (there are exceptions based on age and disability).
• Knowledge of U.S. history and government (civics): Applicants must demonstrate knowledge and understanding of the fundamentals of U.S. history and the principles and form of the U.S. government.
• Attachment to the Constitution: Applicants must be willing to support and defend the United States and its Constitution against all enemies, foreign and domestic. This entails taking an Oath of Allegiance to the United States.
• Selective Service registration: Male applicants who lived in the U. S. between the ages of 18 and 26 must have registered with the Selective Service System or have a valid exemption.