Book:OTRS 3.0 - Admin Manual/Chapter 11/1

OTRS works with many customer data attributes such as username, email address, phone number, etc. These attributes are displayed in both the Agent and the Customer frontends, and also used for the authentication of customers.

Customer data used or displayed within OTRS is highly customizable. The following information is however always needed for customer authentication:
 * User login
 * Email address
 * Customer ID

Use configuration parameters of Script 11.1 in your Kernel/Config.pm file, if you want to display customer information in your agent interface.