The IRS has over 900 different tax forms available to taxpayers when filing their returns. Generally, the average taxpayer doesn't have to worry about a majority of the forms.
Three of these forms (W-2, 1098, and 1099) contain the information you'll need to file your return.
The W-2 indicates your total earnings, if you made contributions to the company's retirement savings and the breakdown of tax withholdings from your salary. The IRS also receives a copy from your employer, so it's important to report the information as accurately as possible.
Homeowners who have a mortgage can expect to receive a Form 1098, documenting the amount of interest that was paid on your loan during the tax year. In many cases, the interest on a mortgage is deductible. Students may also receive a version, the Form 1098-T, which reports payments made to an institution for tuition, or the 1098-E, which shows paid interest on student loans. Both expenses for students may be deductible as well.
There are a variety of Form 1099, including the four most common: 1099-DIV, records dividends, distributions, and capital gains from investments, 1099-INT, which reports investment interest earned, and 1099-MISC, which is for income not sourced from investments, such as freelance work paid by a client. This form documents income received from a party that is not your employer. The IRS gets a copy as well, so they'll be expecting this income to be reported on your return.