Most people who earn income in the United States have to file federal tax forms by April 15 of each year. If you earned income in the U.S. last year and didn't file a tax form, you can still file one, even though the deadline has passed.
EITC, the Earned Income Tax Credit is a tax credit to help you keep more of what you earned. It is a refundable federal income tax credit for low-income working individuals and families. These resources can help you find out if you qualify.