I suggest using Google and entering that question and then reading the results.
<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f1040.pdf">https://www.irs.gov/pub/irs-pdf/f1040.pdf</a>
A tax return is a form you send to the government that shows your income and calculates your tax. The standard federal tax return for individuals is Form 1040.