Form N-426 USCIS policy to provide that only applicants for naturalization under INA §328 or §329 who are currently serving in the U.S. Armed forces required to file a Request for Certification of Military or Naval Service (Form N-426) along with their Application for Naturalization (Form N-400). If you are claiming eligibility for naturalization based on your service in the U.S. armed forces and you are currently serving, you must submit a signed and certified Form N-426 with your Form N-400, Application for Naturalization. Only authorized military personnel may certify your Form N-426. The U.S. Department of Defense confirms whether an applicant for naturalization under INA 328 or INA 329 is serving honorably in an active duty status or in the Selected Reserve of the Ready Reserve by certifying the service member’s qualifying service on Form N-426.