Earned Income Credit is available to help taxpayers 25-65 with a lower earned income that are US citizens or resident aliens. The IRS has a quick quiz, Earned Income Tax Credit Assistant that will determine if you qualify.
There are limitations but the quick quiz will cover it all.
If the quiz says you do qualify, go back through the program thinking about the quiz questions. One of those must be answered differently in your tax return to deny the credit. You can take the quiz as many times as you like while reviewing your return.