How can I automatically generate an order from a requisition, without a previously negotiated agreement?

When entering a requisition, select the Negotiated check box on the requisition line.

Your ability to mark a requisition line as negotiated is subject to your organization's configuration of the application, and your security privileges. You must provide valid supplier information for the requisition. Purchasing terms (prices, terms, conditions, quantity, and so on) must already be negotiated with the supplier.