Employees can use this service to keep their W-4 withholding information current. They can create, change and display the information they would normally include on Form W-4 (Employee's Withholding Allowance Certificate) and on state-specific W-4 forms. This information is used to withhold the correct amount from the employee's salary for taxation purposes. This both reduces the administration necessary in the Human Resources department for entering withholding data into the system and empowers employees to quickly and easily check and change their withholding information when necessary.