Fillable N‑400 Application for U.S. Citizenship

Applying for U.S. citizenship is a major step, and the Form N‑400, Application for Naturalization is the official document you need to submit to U.S. Citizenship and Immigration Services (USCIS). Our fillable PDF version lets you complete the form quickly, accurately, and without any extra software.

Why Use a Fillable PDF for the N‑400?

A fillable PDF provides real‑time validation, automatic date formatting, and easy navigation between sections. You can save your progress, edit fields, and download a clean, printable version ready for your signature.

How to Complete the N‑400 Form Online

Instead of downloading the PDF and opening it in a separate editor, simply click the "Fill out this form" button on this page. The Formize PDF Filler app will load in your browser, and you can start entering your information immediately.

Common Mistakes to Avoid

• Leaving required fields blank: The filler will highlight missing information before you can submit.
• Using the wrong date format: The form automatically formats dates as MM/DD/YYYY.
• Misspelling names or addresses: Double‑check each entry; the filler does not correct spelling.
• Forgetting your USCIS A‑Number: Have your Alien Registration Number handy before you start.

Where to Submit Your Completed Application

After you have filled out the form, download the final PDF, print it, sign it by hand, and mail it to the USCIS Lockbox address listed in the form instructions. You can also submit the form electronically through the USCIS online account if you prefer.

Need more guidance? Review the official USCIS instructions linked at the bottom of the form or consult an immigration attorney.