Illinois Proof Of Service Order-Notice For Income Withholding is a form used in the State of Illinois to inform employers of an order to withhold income from an employee's wages for child support, spousal maintenance, or other court-ordered payments. This form is used to document that the employer has been served with a copy of the order. There are two types of Illinois Proof Of Service Order-Notice For Income Withholding: Non-Docketed and Docketed. Non-Docketed is used when there is no court case number associated with the order. It is signed by an authorized witness who has served the employer with a copy of the order. Docketed is used when there is a court case number associated with the order. It is signed by an authorized witness who has served the employer with a copy of the order, and it is additionally signed by the court clerk.