Which governmental form do you fill out when you begin a job to help your employer withhold the proper amount of taxes?

When you begin a job, you typically fill out the IRS Form W-4, also known as the Employee's Withholding Certificate. This form provides your employer with information about your tax situation, including your filing status and any allowances you may claim. This information helps your employer determine the correct amount of federal income tax to withhold from your paycheck. Some states may also require a similar state withholding form.