If you received unemployment benefits of $10 or more during the tax year, the government agency that paid those benefits should issue you a 1099-G. The form should show the amount of the benefits you received.
Unemployment compensation is generally taxable income to you, so Form 1099-G gives you the amount of unemployment benefits you must report on your tax return. You may opt to have federal income tax withheld on those benefits. If you do, the amount withheld will be reported in Box 4.