Form W-3, also known as the Transmittal of Wage and Tax Statements form, is a vital tax form that employers use to report their employees' total income and withholding to the IRS and the Social Security Administration. When employers issue multiple Form W-2s to their employees, Form W-3 comes into play, summarizing all the salary payments made. It ensures that the authorities receive accurate and comprehensive information about employee earnings. So, it's an important document that helps keep things in order regarding tax reporting.