They are 2 types of sales; Anonymous sales and customer sales. Anonymous sales are sales to walk-in customers. This type of customers don't require their profiles being created. The second type is customer sales, in which case, you create the customer's profile. The former is recommended in shops when you don't necesarily need to keep records of your customers while the latter is recommended espcially in wholesale settings, where credit sales is allowed or when you need to keep a customer list.