Deciding to become a US citizen is an important decision not to be taken lightly. It is not a simple process, so make sure you are aware of all the requirements for citizenship before you make the commitment. There are only two ways to become a citizen, by birth or through naturalization, and each path has its own set of conditions.
When at least one parent is a citizen at the time of birth, then the child is born a United States citizen. If a parent becomes a citizen later in the child's life, as long as the child is less than 18 years of age, then they are also eligible. However some residency questions may need to be addressed. Ideally, children residing outside of the US should be in the legal care of a US citizen parent for application consideration.
Also keep in mind, the US parent should be the one to file the paperwork. If this parent is deceased, then within 5 years of the death, a US citizen grandparent or guardian is an acceptable applicant. Adopted children have a special naturalization process under the Immigration and Nationality Act, search the web for those specific directions.
Adults that are interested in citizenship will need to go through the naturalization process. For the most part, you have to already have a permanent resident card for at least five years. They also expect that you reside in the country for a minimum or 30 months out of the five years. Make sure you have knowledge of US history and government (known as civics), and the ability to read, write, and speak English.
If you meet the necessary requirements, then go ahead and fill out the paper work and get ready for the naturalization test. When your application is accepted you will be fingerprinted at a USCIS facility and interviewed by an officer, this will include questions about your background as it applies to your application. Then you will need to prove your language skills by accurately reading some provided material, and writing a sentence correctly from a provided list. A majority out of the ten questions on the civics test must be answered correctly.
Look for more information about specific requirements if you regularly work overseas, are over fifty years old, have physical or developmental disabilities, or are currently married to a US citizen. There may be exceptions to the necessary requirements if you fit the criteria.
The internet is full materials to help you learn many of the requirements for citizenship in the US. Also look for study aides if you think you might need assistance with the civics test. Spending the time to research can really help you prepare for this important step in your life.