Direct selling means that industrial production enterprises sell products directly to the final target market (that is, consumers) without any intermediaries.
Consignment is a way for industrial production enterprises to entrust their goods to other middlemen for sale. Generally, affiliated companies do not bear the risk of capital investment and sales, but only charge commissions as agreed.
Brokerage sales is a way for suppliers and sellers to exchange information and reach a deal by using brokers or brokerage companies. Brokers don't directly manage goods, let alone take risks, but only bridge the gap between suppliers and sellers and collect "commissions".