Illinois Proof Of Service Notice to Withhold Income For Support is a form required by the state of Illinois for employers to submit to their employees when income is being withheld for child or spousal support. It informs the employee of the amount of income being withheld, the amount of time the income will be withheld, and what entity will be receiving the income. This form is mandated by the Illinois Revised Statutes, Section 750 ILLS 5/510. There are two types of Illinois Proof Of Service Notice to Withhold Income For Support: the Income Withholding for Support (TWO) and the Income Deduction Order (DO). The TWO is used to start the withholding process and the DO is used to modify or terminate the withholding process. The TWO and DO forms must be signed by the employer and returned to the employee. The employee must then provide the signed forms to the obliged or employer.