Fillable N‑400 Application for U.S. Citizenship

Applying for U.S. citizenship is a major milestone, and the first step is completing the USCIS N‑400 Application for Naturalization. Formize lets you fill out this official form directly in your browser—no download, no PDF editor, no hassle.

Why Use the Formize Fillable PDF?

• Instant loading: Click the button and the Formize PDF Filler loads in seconds.
• Auto‑save: Your progress is saved automatically, so you never lose data.
• Secure & private: All data stays encrypted in your browser; we never store personal information.
• Guided help: Inline tooltips explain each field, reducing errors.

Step‑by‑Step Guide to Complete the N‑400

Follow these simple steps to submit a flawless citizenship application:

1. Click "Fill out this form" on this page.
2. Wait for the Formize PDF Filler app to load (usually under 5 seconds).
3. Enter your personal information exactly as it appears on your documents.
4. Answer the eligibility questions truthfully.
5. Upload supporting documents where required.
6. Review the summary screen for any missed fields.
7. Download the completed PDF or print it for mailing to USCIS.

Common Mistakes to Avoid

• Leaving any required field blank – the filler will highlight omissions.
• Using nicknames or abbreviations that don’t match legal documents.
• Submitting an outdated photograph (must be taken within 30 days).
• Failing to sign the form electronically before downloading.

Where to Submit Your Application

After completing the N‑400, you have two options:

• Online filing: Upload the PDF through your USCIS online account.
• Mail filing: Send the printed, signed form to the USCIS lockbox address listed in the Instructions for N‑400 (PDF linked below).

Make sure to include the filing fee and any required supporting documents to avoid processing delays.

Frequently Asked Questions

Below are quick answers to the most common questions about the N‑400 form.