Getting your US Citizenship is also known naturalisation. You can complete the forms, pay the fees and submit by mail or online.
After you have been a Legal Permanent Resident also known as “Green Card” holder, for a certain amount of years, you can apply for citizenship. This is usually three years or five years dependent on how you became a green card holder.
You can apply three months before you actually reach the full three or five years. But, remember there are other conditions or qualifications that you must meet. You must also be in “continuous residence” during that time in the USA. What exactly does that mean? “Continuous residence” means that you have not left the United States for a long period of time. The general rule is that for the three or five years, you have been in the country much more than you have been out.
Another condition that you have to meet is that you have to be paid up in your tax returns or you have some kind of arrangement with the IRS.
You also have to be able to understand, read and write basic English and pass a US Civics test. The test is in English and is done at your interview for naturalization. The interviewer asks you ten questions and you are expected to get most correct. There are many resources to help you study for the test.