You may create a Username for your account so that you don't have to always know your library card number to access various features on your account. To do this, go to the My Account login page  and click on the "Create Username" link that is directly under the "Username or Barcode" box. Follow the instructions to create your Username.
The Username should not be used to login to the library's public computers or various other connected services such as Indiana Digital Media or Freegal. You should use your full card # for these.