The Income Withholding for Support (IWO) form, OMB 0970-0154, sample version has numbers inserted that correspond to the instructions for the form. These instructions provide guidance for completing the IWO form. The IWO is the OMB-approved form used for income withholding in tribal, intrastate, and interstate cases as well as all child support orders which are initially issued in the state on or after January 1, 1994, and all child support orders which are initially issued (or modified) in the state before January 1, 1994 if arrearages occur.