Money 1099-R,1099-K, W-4, W-2, W-9, 1040 and more: What are these forms when filing your taxes? January 12, 2023April 17, 2023Elisabeth Buchwald, USA TODAYComments Off on 1099-R,1099-K, W-4, W-2, W-9, 1040 and more: What are these forms when filing your taxes? There are a lot of different tax forms the IRS requires you or your employer to fill out. Some of the most common ones are the W-2, W-4, 1099 and W-9.