There are four types of ecommerce businesses: business-to-business (B2B), business-to-consumer (B2C), consumer-to-consumer (C2C), and consumer-to-business (C2B).
B2B ecommerce is when businesses sell products or services to other businesses. B2C ecommerce is when businesses sell products or services to consumers. C2C ecommerce is when consumers sell products or services to other consumers. C2B ecommerce is when consumers sell products or services to businesses.
Which type of ecommerce business you have will determine what kind of products or services you can sell, and how you will need to market and sell them.