Form N-600 is the application issued by U.S. Citizenship and Immigration Services (USCIS) allowing a person who is eligible for U.S. citizenship based on the citizenship or naturalization of a parent to request a certificate proving this. It's not an application for U.S. citizenship exactly, but rather a request for official U.S. government acknowledgment that the applicant already holds U.S. citizenship, having gained it automatically, by force of law.
If you have discovered that you're a U.S. citizen based on your parents' citizenship, you're probably eager to get your N-600 done, receive your certificate, and enjoy the rights and privileges of U.S. citizenship right away. However, this result will not happen overnight. USCIS is typically extremely backed up with applications. It needs time to review your application, possibly request follow-up materials from you, and make a decision.
USCIS's average turnaround time can be anywhere from a few months to nearly two years. To get a more accurate estimate of what to expect, visit the Check Case Processing Times page of the USCIS website and select "N-600," then under Form Category choose "application for recognition of U.S. citizenship," and then from the next from the dropdown menu, choose the name of the USCIS field office serving your area. You'll see a time estimate in months, such as "7 months."
Along with filling out and submitting the N-600 form to USCIS, the applicant must provide proof of credentials and pay a fee. All of these can be either submitted online or mailed to USCIS. Then, the waiting begins.
If you are given a receipt notice with a tracking number, you can go to the My Case Status page of the USCIS website.
There, you enter the receipt number, and will be told which step your application has reached. If processing on your application seems to be long finished, but you haven't heard anything from USCIS; or if you did not receive a receipt notice and more months have gone by than is typical; you should contact USCIS to ask what's going on.
In order to do this, you will first need to call the USCIS Contact Center. This can be a major endeavor. It's reportedly best to start in the morning, since you're unlikely to get to a live person without asking for a call-back. (Then make sure you're near your phone and available all day.) It the person you eventually talk to can't resolve the problem, they can make you an appointment to visit a local USCIS office.
If you make an office visit, be sure to bring a photo id and copies of the N-600 application you filed, as well as any evidence of its arrival (such as a postal receipt or copy of your cancelled check) to your appointment.
If you qualify for a certificate of U.S. citizenship, then you also qualify for a U.S. passport. In theory, you don't USCIS's acknowledgment to approach the U.S. State Department and ask for a passport.
In practice, however, getting a U.S. passport without first having a certificate of citizenship can be difficult. The U.S. State department is less accustomed to figuring out who has acquired or derived citizenship than USCIS is.
Nevertheless, there is no harm in trying for a passport without waiting, particularly if you are short on time. Go to the State Department website for information on how to apply for a U.S. passport.
Filing for a U.S. certificate of citizenship might not be as difficult as some of the other immigration forms and processes. However, determining whether someone qualifies for U.S. citizenship, and therefore for this certificate, is often another matter, both for applicants and for USCIS. If you have trouble understanding whether or not you qualify, or you are having difficulty gathering the required documentation or getting a timely and favorable decision from USCIS, consult a knowledgeable immigration attorney.