Fill Out Form N-400 Online in 2026

Form N-400, Application for Naturalization, is the application most lawful permanent residents use to request U.S. citizenship through naturalization. Filing it with U.S. Citizenship and Immigration Services (USCIS) starts your official case. You may also see it called the USCIS N-400 or N-400 application, but the official form number includes a hyphen.

USCIS uses the form to review your identity, background, family details, residence, and travel history. It also checks whether you meet N-400 eligibility rules, such as continuous residence, physical presence, and good moral character. The naturalization process may include biometrics, an interview, and English and civics tests unless you qualify for an exception. If USCIS approves your application, you must take the Oath of Allegiance before you become a U.S. citizen.

You submit an N-400 application to USCIS when you want to become a U.S. citizen through naturalization. It is commonly used by eligible lawful permanent residents and certain military applicants. USCIS reviews your residence, travel history, family details, moral character, and ability to meet English and civics rules before deciding your case.

You may also ask USCIS to share information with the Social Security Administration. This can help you request a Social Security number or card and update your citizenship status after naturalization. Form N-400 also lets you request a legal name change, though the change may depend on a court conducting your oath ceremony.

Get a blank Form N-400 from U.S. Citizenship and Immigration Services (USCIS), a part of the U.S. Department of Homeland Security. USCIS provides the official blank form and current instructions.

PDFLeader also has a blank Form N-400 preloaded in our browser-based editor, so you do not need to download a template from another source. You can fill out the form and download the completed PDF for future use. PDFLeader does not submit or file Form N-400 with USCIS.

File Form N-400 with U.S. Citizenship and Immigration Services (USCIS). For online filing, sign in to your USCIS online account and complete the N-400 application in the USCIS portal. A downloaded PDF is not filed automatically, so use it as a saved copy or reference when entering your details online.

For paper filing, print the completed form, sign it as required, and mail it with the fee and supporting documents. If you request a reduced fee or fee waiver, you must file by mail, not through the portal. USCIS does not use one mailing office for every application. Check the current USCIS direct filing address for your eligibility category and location before mailing it.

A lawful permanent resident seeking U.S. citizenship must complete Form N-400 and confirm their N-400 eligibility, personal history, and answers under penalty of perjury. If a qualifying disability or mental impairment prevents the applicant from completing the naturalization process, a legal guardian, surrogate, or eligible designated representative may act for them. A lawyer, paralegal, or other preparer may help, but the applicant remains responsible for the information provided.

After filing, USCIS officers use Form N-400 to review the case, run background and security checks, and conduct the naturalization interview. The applicant must attend the interview and, unless exempt, take the English and civics tests. USCIS then decides the application and, if approved, arranges the Oath of Allegiance.

You can add a simple electronic signature to Form N-400 on our platform, then download it. PDFLeader does not submit the form. For paper filing, USCIS requires a handwritten signature and does not accept a typed, stamped, or autopen signature. If you file online, sign through the USCIS system as directed. Check the latest Form N-400 instructions and USCIS updates before signing and filing.

Start with Information About Your Eligibility and select only one box. For Your Current Legal Name, use the name on your birth certificate or the name set by marriage, divorce, or court order. Keep the related certificate, decree, or court order with your N-400 document checklist if your name changed. Enter Your Name Exactly As It Appears on Your Permanent Resident Card and have the card ready. Enter “N/A” if you do not have one.

Next, provide any Requested Legal Name Change and complete Biographic Information. Gather your Current Home Address, any separate Mailing Address, and your Physical Address History for the past five years if the general provision applies. For Information About Your Marital History, report every marriage, including annulled marriages, and use your marriage and termination records to confirm the details.

Form N-400 has no fixed deadline. You may submit your N-400 application up to 90 calendar days before you complete the continuous residence period required for naturalization. This period is usually five years as a permanent resident or three years if you qualify based on marriage to a U.S. citizen.

There is no upper time limit for filing Form N-400. You can wait after completing the required residence period, but filing before the 90-day early filing window may cause USCIS to deny your application.

Form N-400 is not required when a child automatically becomes a U.S. citizen under INA Section 320. This may happen if you naturalize while your child is under 18, unmarried, and a lawful permanent resident living in your legal and physical custody.

A person born abroad who acquired U.S. citizenship through a U.S. citizen parent also does not apply for naturalization. That person may file Form N-600 to request a Certificate of Citizenship. Form N-600 documents existing citizenship, rather than granting it.