E-commerce refers to the buying and selling of goods and services over the internet and other computer networks. It allows businesses to operate more efficiently by reaching wider markets and customers to shop conveniently without time or location constraints. Major types of e-commerce include business-to-business (B2B), consumer-to-business (C2B), consumer-to-consumer (C2C), and business-to-consumer (B2C). While e-commerce provides benefits like lower prices, more product choices, and 24/7 shopping, it also poses risks such as inability to physically examine products and potential data and identity theft.