The more information agents have about the customer, the better they will be able to assist them. A customer form can be used to collect additional information about them, such as whether they have previously contacted support, whether they are paying customers, and what features were promised to them and when.
This form does not have to be completed by customers. After gathering basic information from the customer, such as their email address, the agents who speak with these customers can fill out the remaining information. When the customer contacts support again, the agent dealing with the customer can review the information in the form and gain context.