Child Support Forms ; 4-8c. You can go to court to file the petition or go online to New York State DIY (Do-.It-Yourself) Forms at nycourthelp. The IT2104 form is an essential document for New York employers when it comes to payroll administration. What is child support, and how to calculate it in New York state? Our Child Support Guide will give you the answers you're looking for. Every employee is required to complete a federal Withholding Allowance Certificate (W-4), which can also be utilized for state and local withholdings.