E-commerce involves the exchange of goods and services using electronic means like the internet. It requires a product, a website to display and sell the product, marketing to drive traffic to the site, an ordering system to accept orders, a payment system like credit cards, fulfillment to ship products, support for returns and issues. The main product categories sold online include computers, books, music, financial services, and more. E-commerce provides advantages like access to worldwide markets but also challenges like no personal contact and costs of infrastructure. Setting up an online store requires elements like promotion, an online catalog, purchase and payment systems, delivery, and customer support.