Complete Form W-4 so that your employer can withhold the correct federal income tax from your pay. Give Form W-4 to your employer.Part 1 – Complete this part to calculate your withholding allowances for New York State and Yonkers (line 1 of Form IT-2104). File original documents along with a detailed written record of any relevant conversation with the employee in the employee's personnel file. Learn stepbystep instructions on how to fill out a W4 form, whether you're single, married, or filing jointly. Complete Form IT-2104 each year and file it with your employer if the number of allowances you may claim is different from federal Form W-4 or has changed. Information about Form W4, Employee's Withholding Certificate, including recent updates, related forms and instructions on how to file. Before making any entries, see the Note below, and if applicable, complete the worksheet in the instructions. This video goes over how to fill out a 2021 Form W-4 if you are single and the basics behind Form W-4. Mary is a human resources officer who is filling a vacant administrative position at her company.