The main documents to use for proof of citizenship are a birth certificate or a previous passport. Birth certificates used as evidence of citizenship cannot be copies. They must be certified with a raised, embossed or impressed seal. If you are submitted a previous passport as proof of citizenship and it is damaged, you must prepare a signed statement addressed to the U.S. Department of State explaining how the damage occurred.
For citizens born abroad, a Consular Report of Birth Abroad or Certificate of Record of Birth will suffice as evidence of citizenship. Naturalized citizens can present a Naturalization Certificate or a Certificate of Citizenship.
In addition to the proof of citizenship, which is typically a type of birth record, you must also present current identification. Naturalization certificates and previous passports serve as evidence of both citizenship and identification. Otherwise, a driver's license or government or military ID is accepted. However, If you are using a license from a state different than the state where you are submitting your passport application, you need to provide secondary identification, preferably with your photo and date of birth.
You are also required to bring a photocopy of the front and back of both of these documents and the proof of citizenship on a white, letter-sized sheet of paper.
With your documents and application, you must provide two passport photos. One will be kept on file with your application and the other will go in your passport. There are strict quality requirements for these photos, so it is worth taking the time to get them done properly before heading to the passport office. The photos must be identical, color, two-inches by two-inches square photos showing you in everyday clothes without a hat or sunglasses. Your face from the bottom of the chin to the top of the head needs one inch to one and three-eighths of an inch of the frame.
Before you arrive at the passport agency or acceptance facility, you should fill out form DS-11, named "Application For a U.S. Passport." This form is available online and you can fill it out digitally or print a copy and fill it out by hand. Don't sign the application before you apply in person, though, because the signature must be completed in the presence of an acceptance agent.
