N-400 Form: How to Apply for U.S. Citizenship (Naturalization) — Complete 2026 Guide
Form N-400 is the official USCIS Application for Naturalization that green card holders file to become U.S. citizens. This complete 2026 guide covers N-400 eligibility, required documents, filing fees ($710–$760), step-by-step instructions, processing times, and what to expect at your naturalization interview.