# Application Modules - Overview

Module is typically considered to be an add-on to the application that extends the functionality of some parts of the system. It usually has fewer options that are configurable by the end user, but may also handle and store of information in the database.
In ApPHP Framework terms a module is a self-contained software unit (a special case of application extension) that consists of models, views, controllers and other supporting components. In many aspects, a module resembles to an application. The main difference is that a module cannot be deployed alone and it must reside inside of an application.
Users can access the controllers in a module like they do with normal application controllers. Module repeats the MVC structure. Each module usually serves for a single purpose and may be easy installed/uninstalled and moved from one application to another.
You have to write special procedures to handle Modules Management, editing, installation, etc. Such features already exist in Directy CMF. Examples of modules:

- Setup
- News
- Testimonials
- Payments
- etc.