The 1040 form is the standard United States federal tax form used to file individual taxes, the first first of which was printed in 1913. Until 2009, this form, and the accompanying documentation, was mailed to each American household every year.
The form, or a variant of it, is required to be filled out by every taxpaying American before a specified date (most often April 15) annually. The two-page form collects taxpayer identification information and information about income earned from a variety of sources.
This information is then used, on the second page of the form, to calculate the amount of taxes the individual was liable for and, depending on how much they paid throughout the year, how much they either still owe or are owed.
Additional forms and worksheets are sometimes required to determine some of the information on the 1040 form. In some cases these forms are also mailed back to the IRS as supporting documentation.