Before making any entries, see the Note below, and if applicable, complete the worksheet in the instructions. Complete Form W4 so that your employer can withhold the correct federal income tax from your pay.Consider completing a new Form W-4 each year. Complete Form W-4 so that your employer can withhold the correct federal income tax from your pay. Additional withholding amounts​​ To ask your employer to withhold an additional amount each pay period, complete lines 3, 4, and 5 on Form IT-2104, as applicable. Withholding Tax Forms and Instructions To ensure you are able to view and fill out forms, please save forms to your computer and use the latest. NC-4 Employee's Withholding Allowance Certificate. Documents. Contact Information.