Settings Modules extend the PageCarton core class PageCarton_Settings. It allow plugin developers to take variables from the plugin installer or user. The information filled in by the user may be used by the plugin developer to alter the behavior of the application.
A simple, yet perfect scenario is a plugin that takes feedback from site users and send as email to the website admin. Such plugin may want to ask for admin e-mail address to send the feedbacks to.
The process of creating a settings module is similar to the other modules:
PageCarton Admin Panel > Plugins > My Plugins > "New Settings"