Customer data integration is about connecting all of the different pieces of information that you have about a customer. For example, let's say you have a store where you sell clothes and you have a website that people can buy from. You would need to keep track of all the different things you know about each customer, including their address, phone number, email, and what kinds of clothes they usually buy. Customer data integration helps you create a single record with all of this information together, so you can keep track of all of your customers in one place.