If you are going to use the sales, accounts receivable, retail capabilities in Dynamics AX you will need to create customers to manage the credit you are extending to them and for other business administration tasks. A customer in Dynamics AX is actually considered a role or a party. To create a customer you first need to create a party in the global address book and then create a role for that party which would be a customer in the specific legal entity that you are going to do business with that customer. The customer record is then assigned with the specific attributes or parameters on how you want to control and manage that customers.
In this video we walk through a manual process of creating a customer.
Keep in mind that there are actually a few ways to create the customer. For example if you are using the e-commerce functionality in retail the customer can create their own record when they make a purchase. You will see some of the other ways in other videos on the site.