8 Vendor number - This field is not mandatory, only delegated purchasing agents are required to complete this area. Insert the vendor number, which may be obtained from a previous purchase order or by using the Vendor Inquiry option of the Purchasing System Inquiry website at: http://www.bussvc.wisc.edu/purch/purchinq.html. Each vendor order address is assigned a vendor number which combined with the requisition number becomes the 13-digit purchase order number. If the vendor number you are looking for does not exist, contact Purchasing Services to have a number assigned.