Question types are part of the question engine and not actually a module. However, they are a core piece of the quiz module and are designed to be used by other activity modules.
A question, in Moodle speak, is the set of definitions that make up a reusable interactive element used for assessment. These definitions include the question text, its possible answers, any grading requirements, feedback to responses, and more.
A question type is a pluggable unit in the question engine that provides all of the definition and functionality of an assessment. They can be managed from the Questions menu item on the front page and any course administration menu, or from the quiz activity editing screens.
The Questions menu (shown in the following screenshot) allows you to create, edit, view, and manage questions into categories. You can also import questions to and export questions from a variety of question formats.
There are a number of standard question types...