Distribution of goods is wholesaling by designated wholesalers. The designation is done by a product manufacturer, who assigns a wholesaler to serve as a distributor for its goods. This is often tied to a particular territory. This would usually be formalized by a written agreement between the manufacturer and the distributor.
Distribution may or may not have an exclusivity element. In other words, a distributor may be the only official wholesaler of the given goods in an assigned territory, or other wholesalers may have a right to sell that product too. In the latter case, the official distributor would usually have certain benefits, for example marketing support from the brand owner.