What is it all about?
Drupal is a free open-source content-management framework written in PHP. It's a content management system (CMS) that allows free construction and management of websites and other network applications (such as smartphone apps).
Provides for self-management of site structure and content. Provides a ready-made software components, and a set of rules to regulate and allow an extension with code. It's easier to customize components—views, lists, blocks, admin tools, and more