N-400 Application for U.S. Citizenship – Fillable PDF

Welcome to Formize.com – the fastest way to complete the USCIS N-400 Application for Naturalization without downloading a PDF editor. Our Fill out this form button opens the official N-400 PDF directly in the Formize PDF Filler, letting you type, save, and print your citizenship application in minutes.

What Is the N-400 Form?

The N-400 is the official United States Citizenship and Immigration Services (USCIS) form used by permanent residents to apply for naturalization. It collects personal information, residency history, employment details, and eligibility questions required for the citizenship interview.

How to Fill the N-400 Online with Formize

Our cloud‑based Formize PDF Filler turns the static PDF into a fully interactive, fillable document. Follow the simple steps below to complete your application without installing any software.

Common Mistakes to Avoid

• Leaving required fields blank: The form will highlight missing information before you can save.
• Mismatched dates: Ensure your residency and travel dates add up to the required continuous residence period.
• Incorrect name format: Use the exact name as it appears on your Green Card and other legal documents.
• Skipping the signature page: The PDF filler lets you add a digital signature; you must still sign the printed copy before filing.

Where to Submit Your Application

After completing the form, download the filled PDF, sign it on paper, and mail it to the USCIS lockbox address listed in the Instructions for Form N-400. You can also submit the form electronically through your USCIS online account if you prefer.

Need Help? Resources & Support

For detailed guidance, consult the official USCIS N-400 page. If you have questions about the fillable PDF process, our Help Center provides step‑by‑step tutorials.