Cross-selling is a sales technique that involves encouraging a customer who has purchased a product or service to also purchase a related product or service. This technique is often used by companies that offer a range of products or services, as it provides a way to increase the value of each customer by encouraging them to buy more.

For example, a company that sells smartphones might use cross-selling to encourage a customer who has purchased a smartphone to also purchase a case or screen protector for their phone. This would help the company increase its revenue from the customer, as they would be buying more than just the phone