But intentions are not binding contractual conditions. Nor need they lead up to binding contractual conditions. Moreover a letter expressing intent, in its form, does not adequately suggest what the appropriate response should be. Whereas a Request for Quotation / RFQ quite literally is a Request. For a Price Quotation. Hence the document's name, it meaning is expressed by it's name. Hence an appropriate response, for a vendor or supplier, is issuing a a price quote.
On Offer acceptance there is either a contract generated or a pro forma invoice generated. Since the offer is binding once accepted, the offer if well enough detailed and advised can and often does take the place of the contract. Customarily in Real Estate transactions the purchase offer itself is generally also the contract for purchase as well. The offer becomes a binding contract once accepted.