Mail order is the buying of goods or services by mail delivery. The buyer places an order for the desired products with the merchant through some remote methods such as:Sending an order form in the mail Placing an order by telephone call Placing an order with a travelling agent Filling in an order form on a website or mobile app — if the product information is also mainly obtained online rather than via a paper catalogue or via television, this mail-order model is called online shopping or e-commerce