User Authentication is used to allow users to log into a system, and once inside, continually monitor them and allow their navigation from page to page. Authentication consists of storing user credentials in a database, matching those credentials to login input, tracking the 'session', and controlling what pages and content a given user has permision to see. For example, a learning management system (LMS) might have several levels of access, one for administrators, another for teachers, and another for learners. Every time a user navigates to a new page, their session and credentials are seamlessly re-checked for both security and to provide accurate site navigation. Most sites I work on have some type of authentication.

While design aspects on a given site vary, a typical login form consits of these features:

Once authenticated, the user sees a welcome screen and is then re-directed to the site's internal home page: