E-commerce involves the buying and selling of goods and services over electronic systems like the Internet. There are several types of e-commerce depending on the target audience, including business-to-consumer (B2C), business-to-business (B2B), consumer-to-consumer (C2C), and consumer-to-business (C2B). The document outlines some pros and cons of e-commerce, such as greater reach but lower costs as pros, and difficulties accessing certain sectors and not being able to see products as cons.