To apply for US citizenship, an eligible Green Card holder must file Form N-400 and to become a US citizen, a foreign national must first become a Green Card holder, that is, he must become a lawful permanent resident of the United States. To become a lawful permanent resident, his US citizen family member or a US employer must file an immigrant petition, for him. Otherwise he must participate in the official Diversity Visa or the Green Card lottery program and become eligible for an immigrant visa.
However, he may not become a US citizen as soon as he becomes a Green Card holder and he must wait for five years and satisfy few eligibility requirements, after obtaining a Green Card, to apply for naturalization. And to do so, he must file the USCIS Form N-400, which is an application for naturalization. If his application for naturalization is approved and if he is found to be eligible to become an American citizen, he will be granted US citizenship.
If you had become a Green Card holder by getting married to a US citizen, then you need not wait for five years to apply for citizenship, as you may file Form N-400, three years after being granted lawful permanent resident status in the country. That applies only if you are living with the same US citizen at the end of the three year period.
If you believe that you are capable of becoming a US citizen, you will have to file the USCIS Form N-400, along with certain supporting documents and the filing fee. The form filing fee is $595 and along with that you will have to pay $85, for biometrics. Hence the total fee $680, must accompany your naturalization application. You will have to go through the form instructions to know about the payment details. Military applicants need not pay the filing fee. Similarly, if you are above age 75, you may not be required to pay the biometric fee. A fee waiver request may be filed, if you feel that you are eligible for a waiver.
Many Green Card holders are demotivated and they do not apply for US citizenship though they are eligible as they feel that the Form N-400 filing fee is too high. But they fail to understand the fact that US citizenship grants them a variety of rights and benefits. On becoming a US citizen, you may not be questioned about your lawful status in the country and you will be treated equally with the native citizens of the country. Moreover, you may travel outside the country freely and you need not wait for a long time in the airports to re-enter the United States.
Moreover, you need not worry about Green Card renewal, if you are granted US citizenship. And you will be granted the right to sponsor Green Cards for few different categories of relatives and you can help them to immigrate to the country. The most important privilege is that you may take part in the civic life and vote in the federal elections. Hence it is worth paying a fee to obtain US citizenship through naturalization. And if you look forward to become a citizen of this great nation, file Form N-400 now.