The Password preference is used to set restrictions on the password for users in the system.

The minimum number of characters required for a password.
The minimum number of digits required for a password.
The minimum number of special characters required for a password.
The number of days before a password expires.
A checkbox to allow characters to be repeated in a password.
The number of attempts a user has to enter their password before they are locked out of the system.
A checkbox to send an email to the admin when a user fails to sign in.
A checkbox to force a user to change their password on their next sign in.