To become a U.S. citizen ("naturalize"), you must, after determining that you are eligible, fill out an application form, sign it, and send it to U.S. Citizenship and Immigration Services (USCIS). Most people have to pay a fee or ask USCIS to allow them to apply without a fee. There are a few documents USCIS wants you to include with the application form, but other than that, there is nothing else you need for your application.

Online Naturalization Application Filing Option

Naturalization can be applied for online with USCIS, if you want to do it that way instead of by mail. If you are applying based on military service, are applying from outside the United States, or are applying for a fee waiver or reduced fee, however, you cannot file your application online.

If you plan to apply online, you must create an online account with USCIS first. Follow all the instructions on the site to successfully complete your application.

The U.S. Citizenship Application Form

The application form is called N-400, Application for Naturalization. This is a government form that comes from USCIS, so don't go looking for it anywhere else. The best place to find it is on the USCIS website. The best way to view, print, or fill out the forms is with pdf software such as Adobe Reader.

If you do not have Internet access or would prefer to fill out the application form by hand, USCIS will mail you the form; call USCIS customer service at 800-375-5283. For TTY (deaf or hard of hearing) call 800-767-1833.

For an explanation of how to fill out the N-400 application form, see Filling Out Naturalization Application Form N-400.

If you choose to apply for naturalization online rather than by mail, USCIS offers an online version of the N-400 for you to fill out.

Paying the USCIS Fee or Requesting a Fee Waiver

At the same time you send your application for naturalization, you must send USCIS the filing fee (if you are required to pay one) or a request that you be able to file the application without a fee (a request for a fee "waiver").

To find out whether you must pay a fee, how much it is, and whether you can request a fee waiver, see USCIS's instructions for Form N-400.

If you must pay a fee, there are several ways to do it: check, money order, or credit card. These are the only things USCIS will accept. Do not send cash. If you're applying online, follow the instructions for payment that USCIS provides to you.

You must submit all fees in the exact amount. If you send more or less than the correct fee amount, USCIS is not going to send you a bill or a refund. Instead, your application will be rejected and whatever you paid will be sent back to you.

Paying N-400 Application Fee by Check or Money Order

Checks or money orders must come from a bank or other financial institution located in the United States and must be in U.S. dollars. Make your check or money order payable to "U.S. Department of Homeland Security"—exactly that way. Don't use initials like "DHS."

If you live outside the United States, contact the nearest U.S. embassy or consulate for instructions on how to pay.

Paying N-400 Application Fee by Credit Card

To pay the application fee by credit card, you need to fill out USCIS Form G-1450, which gives USCIS your credit card information. The form, along with instructions on how to fill it out, is free from the USCIS website.

Make sure to complete all three sections and sign it. When you send your application package, place your Form G-1450 on top of your Form N-400.

You must use a single credit card. You can't split your fee payment between different cards.

Requesting an N-400 Fee Waiver

If you believe you are eligible for a fee waiver, complete Form I-912, Request for Fee Waiver and submit it and any required evidence of your inability to pay the filing fee with your N-400. Form I-912 is a USCIS form, and is free, including instructions for filling it out, on the USCIS website.

USCIS will also accept a written request for a fee waiver (plus any evidence to support your request) instead of a Form I-912.

Documents to Submit With Form N-400

USCIS asks for a few documents at the time you apply for naturalization. Any other documents USCIS might need to see can be brought to your citizenship interview.

For a discussion of the documents that are necessary to send at the time you apply, see What Documents Should I Send With My N-400 Application for U.S. Citizenship?

Where to Send Everything

If you're filing by mail, put your completed N-400 application form, fee (or fee waiver request), and documents together in one package. The address you send the package to depends on a few things. Below are the addresses required in 2018.

First, if you're applying based on being a current or former member of the military, a spouse of a current member of the military, or a close relative of a deceased member of the military, and you're using the U.S. Postal Service (including their priority or overnight service), send your application package to:

USCIS
P.O. Box 4446
Chicago, IL 60680-4446

Or, if you're using a delivery service such as FedEx, UPS, or DHL, send it to:

USCIS

Attn: Military N-400
131 S. Dearborn, 3rd Floor
Chicago, IL 60603-5517

For everyone else, the mailing address depends on where you live and how you send it. If you live in Alaska, Arizona, California, Colorado, Micronesia, Guam, Hawaii, Idaho, Kansas, the Mariana Islands, Montana, North Dakota, Nebraska, Nevada, Oregon, Utah, Washington, or Wyoming, and you're using USPS (including their priority or overnight service), mail your application package to:

USCIS
P.O. Box 21251
Phoenix, AZ 85036

If you live in one of those states and are using a delivery service such as FedEx, UPS, or DHL, mail it to:

USCIS
Attn: N-400
1820 E. Skyharbor Circle S
Suite 100
Phoenix, AZ 85034

If you live in Alabama, Arkansas, Connecticut, Washington DC, Delaware, Florida, Georgia, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Mississippi, North Carolina, New Hampshire, New Jersey, New Mexico, New York, Oklahoma, Puerto Rico, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, the Virgin Islands, Vermont, or West Virginia, and are using USPS (including their priority or overnight service), mail your application package to:

USCIS
P.O. Box 660060
Dallas, TX 75266

If you live in one of those states and are using a delivery service such as FedEx, UPS, or DHL, mail it to:

USCIS
Attn: N-400
2501 S State Hwy 121 Business
Suite 400
Lewisville, TX 75067

If you live in Illinois, Indiana, Wisconsin, Iowa, Michigan, Minnesota, Ohio, Missouri, or Pennsylvania, and are using USPS (including their priority or overnight service), mail your application package to:

USCIS
P.O. Box 4380
Chicago, IL 60680-4380

If you live in one of those states and are using a delivery service such as FedEx, UPS, or DHL, mail it to:

USCIS
Attn: N-400
131 S. Dearborn, 3rd Floor
Chicago, IL 60603-5517

If you're applying online, follow the instructions you are given on the site for submitting the form, payment, and documents.