Free Citizenship Guide & Document Checklist

The path to U.S. citizenship looks straightforward from the outside — file the right form, pass the test, take the oath. The reality is that the right form depends on whether you are becoming a citizen or proving citizenship you already have, and choosing the wrong one wastes time and filing fees.

This free guide, prepared by Passage Immigration Law attorneys, breaks down the difference between Form N-400 and Form N-600, walks through the eligibility requirements for each, and gives you a complete document checklist so you can put together a strong application.

What’s inside the Citizenship Guide and Document Checklist

• Clear breakdown of Form N-400 vs. Form N-600 — when to file each form, who qualifies, and how the processes differ
• Eligibility requirements for naturalization (N-400) and Certificates of Citizenship (N-600), including residence, physical presence, English/civics, and good moral character standards
• Detailed document checklist for each application — exactly what to gather before you file, including originals vs. copies, certified translations, and supporting evidence
• Common mistakes we see from clients who came to us after a denial or delay
• 2026 filing fee notes and where to verify the current fee against the USCIS schedule

Who should download this guide

This guide is most useful if you are:

• A lawful permanent resident approaching the residency threshold for naturalization (five years in most cases, three years if married to a U.S. citizen) and starting to put together your N-400.
• Born outside the United States to one or two U.S. citizen parents, and trying to figure out whether you acquired citizenship at birth and need an N-600 to prove it.
• A green card holder whose parent naturalized while you were under 18, and wondering whether you derived citizenship under the Child Citizenship Act of 2000.
• An adoptive parent of a child who entered the United States on an immigrant visa and may now qualify for the N-600 process.
• A spouse, employer, or family member helping a loved one think through whether they are ready to file.

Why the right form matters

Form N-400 is the application to become a U.S. citizen through naturalization. The applicant is a green card holder asking USCIS to grant citizenship. The case includes the English and civics tests, the good moral character review, and the oath ceremony.

Form N-600 is the application for a Certificate of Citizenship — for someone who already became a U.S. citizen automatically through a parent and now needs a certificate to prove it. There is no test, no oath, and the analysis turns on dates and the parent’s U.S. residence at the time the applicant was born or naturalized.

Filing the wrong form is more than a paperwork mistake. We see clients who paid a naturalization filing fee and went through interview prep, only for USCIS to determine they were already citizens. We also see clients who filed N-600 without verifying their parent’s U.S. residence and received denials that took months to unwind.

How Passage Immigration Law approaches citizenship cases

Every citizenship case at our firm starts with a timeline review — parents’ citizenship history, applicant’s residence and travel, marriages, criminal contacts, and tax history. Once that timeline is on paper, the right form usually picks itself. From there we prepare the application, supporting evidence, and interview prep so the client walks in confident.

If you are not sure where to start, the free guide is the right first step. If you would prefer to talk through your specific situation, you can request a consultation with our team.

Related reading

• Citizenship and Naturalization Services
• Form N-400 vs. Form N-600: Which Citizenship Form Should You File?
• Good Moral Character and Naturalization
• Am I Already a Citizen Even Though I Was Born Outside the U.S.?
• All Free Immigration Guides