W-4 is the tax form that is: Responses officially called "Wage and Tax Statement". officially called "Wage and Tax Statement". the document an employer is required to send to each employee and the IRS by the end of January. the document an employer is required to send to each employee and the IRS by the end of January. completed by an employee in the United States to indicate his or her tax situation to the employer. completed by an employee in the United States to indicate his or her tax situation to the employer. completed when filling for tax return by April 15th.