The most common requirement for business is to add the delivery charges with the quotation, the delivery charges have to be computed based on some formula or rules given by the delivery company.
Delivery cost, in case of wholesale, is paid by either customer or supplier depending on the negotiation and most of the time cost of the delivery it is given by the shipping company as the shipping consignments are huge, the cost of the delivery cannot be estimated in advance.
Odoo have a built-in delivery computation framework that allows you to configure the delivery rules, to compute the delivery cost based on distance, weight, volume, sale price of the product or you can integrate with delivery service provider such as DHL, FedEx, UPS, USPS, to get the delivery price in real time. Such delivery providers are useful when you have an e-commerce store and your customer wants to choose delivery cost by themselves.