Use the entry form to capture everything you want, including services, SOWs with deliverables, work orders and items with scheduled payments.
Workflow routes for financial and budget approval as well as procurement and subject matter expert review, where necessary. Alerts warn the requisitioner of potential issues. Procurement may even create spot bids leveraging sourcing functionality to get competitive offers before ordering.
For users, their requisition is the central place to group everything they need, across suppliers and orders. It becomes the way to track through the orders to delivery, receipt and invoice as well.