Buyers float RFQs without committing to buy the goods.
Buyers are obliged to accept the delivery of the goods and pay the counter-value of the goods (according to the agreed payment terms) only after the online submission of the purchase order. The supplier that receives the purchase order is obliged to deliver (and receive the payment for) the item lines of the received purchase order that have been (re)confirmed online.
Briefly said, the transaction is closed and a sales and purchase contract is established only when a buyer has submitted a purchase order that has been reconfirmed by the supplier.
Purchase order confirmations can be partial (some lines of the PO) or complete (all lines of the PO).