Which form do employees use to report their annual income taxes?

The correct form for employees to report their annual income taxes is Form 1040 or 1040A. This form is specifically designed for individuals to report their total income, claim tax deductions and credits, and calculate their tax liability for the year. Completing and submitting this form is crucial as it provides the IRS with a comprehensive account of an individual's earnings, taxable income, and the taxes owed or refunded.

Form W-4, on the other hand, is primarily used by employees to inform their employers about their tax withholding preferences and does not report annual income taxes. Form I-9 is used to verify an employee's identity and eligibility to work in the United States, while Form 1099 is issued to report various types of income other than wages and salaries. Therefore, Form 1040/1040A is the appropriate document for filing annual income tax returns.