Complete Form N400 to apply for naturalization and provide the required documentation. You have been a legal permanent resident for 3 years or more and meet all eligibility requirements to file as a spouse of a U.S. citizen.You need to be at least 18 years old, be a permanent resident with a green card for a least 5 years, 3 years if you are married to a US citizen. The IRC can help you to petition to bring your family members to the US, apply for citizenship, green cards, work authorization, travel documents, and more. Your Form N-400, Application for Naturalization, was placed in line for oath ceremony scheduling. If USCIS approves your Form N400, Application for Naturalization, we will schedule you to take the Oath of Allegiance at a naturalization ceremony. ICP's DOJ accredited representatives will provide one-on-one consultations to determine whether you are eligible for citizenship. Show that you have lived for at least 3 months in the state or USCIS district where you apply. You can apply for a US passport for yourself or your children under the age of 18 whom have automatically been granted citizenship based on your status. Want to apply for US citizenship?