The user ID is the set of numbers on your library card. Your password is the PIN code of your library card. More instructions: Login and My account.
When you log in using your library card, the service will store the library card number and PIN code as well as your name, email address and home library.
When you log in using your email address, the service will store your name, email address and home library.
Read more about management of personal information on the Data protection page.