Catalogs are mostly used by mail order firms. Mail order firms are businesses that allow customers to order products remotely, without visiting a physical store. Customers can browse products in a catalog, select the items they want to purchase, and then place an order by mail, phone, or online. Catalogs are an important part of the mail order business because they provide a convenient way for customers to view and select products. Catalogs typically include detailed descriptions of the products, along with photographs and prices. They may also include customer reviews and recommendations to help customers make informed purchasing decisions. By using catalogs, mail order firms can reach a wider audience of customers who may not have easy access to physical stores or who prefer the convenience of shopping from home.