The procedure is almost the same. Notice issued by the bid inviting unit-purchase of bidding documents (registration)-participation in bid opening-end. The formats of the two bidding documents are similar. If you know there are bids, you will understand why there are three bidders, two bidders, 1 bidder.
Single-source procurement, also known as direct procurement, refers to the way that the purchaser purchases from a single supplier. It is applicable to the situation that the purchase restriction standard and the open tender amount standard are met, but the source of the purchased goods is single, and it is patent, pre-manufactured, contract added, and the original purchased project is subsequently expanded, so it is impossible to purchase from other suppliers in an unforeseen emergency. The main feature of this procurement method is that it is not competitive.
Public bidding is the main procurement method of government procurement, which means that the purchaser invites all potential unspecified suppliers to participate in bidding by issuing a tender announcement in accordance with legal procedures. A procurement method in which the purchaser selects the winning supplier from all the bidding suppliers through some predetermined criteria and signs a government procurement contract with them.