A common requirement is to allow a user to request that login information be sent to their email address. When the User table is configured with an Email address field, then the Sign In control contains the Forgot your password? link.
When the User clicks this link, they are taken to the page to Retrieve User name and Password.
Enter the email address associated with your account and the (optional) captcha information and then click Send. Any Sign In information will be sent to the email address.
Configuring Application Security