When you meet all the requirements to U.S. citizen, you need to file an application at USCIS office. The form N-400 is required for filing U.S. citizenship. Before applying this form you should read all the requirements and procedure of filing application. For this, you can read A Guide to Naturalization on USCIS website www.usics.gov. You can also call USICS National customer center at 1-800-375-5283. In case of some applications, additional English and Civics tests are also taken. This depends on the period for which applicant has been living in the country and his or her age. You need to check eligibility and requirements for filing form N-400 carefully.
Form N-400 should be filled in black ink. You need to answer all questions. If an item is not applicable to you write N/A. Go through step by step instruction for filing the form at http://www.uscis.gov/files/form/n-400instr.pdf. This will help you to fill the form correctly and accurately. After completing the application form, accompany it with required documents and application fees and mail to appropriate USCIS office. The filing fees of form N-400 is $680 ($595 filling fees + $85 biometric fees, wherever applicable).
If by any reason your application for U.S. Citizenship gets rejected, you can file a motion to reopen your case. For reopening your case in USICS office you need to fill form I-290B. The filing fee for this form is $630. You need to submit the documents and the fee at the desired filing address to reopen the case. Make sure you complete all the fields in the form correctly and accurately. To ensure that your form is accepted you need to complete and sign the form. To avoid rejection, go through step by step information to file form at http://www.niwus.com/files/Form_I290B.pdf. The fee is non-refundable irrespective of the decision that USICS takes. Also, you will be notified of any decision taken on your appeal. If you change your address during the period of filing an appeal, make sure you send written application to USICS office stating the change of your address. You can take help of USCIS customer center anytime.