Drupal is a framework that is open source and can be used by publishers and developers to handle content. Its main function is to manage content for websites, providing the structure for website developers to design and develop sites without extensive backend programming. Additionally, programmers and developers can utilize a base code in Drupal, which is based on PHP, for application development. Furthermore, Drupal offers themes and frameworks that developers can use to customize sites and publish content online for their employer or personal website.