Drupal is a free and open-source content management system (CMS) that is used to build and manage websites. It is written in PHP and is based on a modular architecture, which allows developers to add or remove features as per their requirements.

Drupal provides a powerful set of tools for creating and managing websites, including content creation and management, user authentication and permissions, and custom design and theming options. It is also highly extensible, with a vast collection of contributed modules available to add functionality to your site.

Drupal is known for its flexibility, scalability, and security features. It is used by organizations of all sizes, including small businesses, non-profits, and large enterprises, to build and manage their web presence.

Some of the key features of Drupal include:

• Customizable content types and fields
• Advanced user and access control
• Multilingual support
• Search engine optimization (SEO) tools
• Responsive design and theming options
• Built-in caching and performance optimization
• Integration with third-party tools and services.

Overall, Drupal is a powerful and flexible CMS that can be used to build a wide range of websites, from simple blogs to complex e-commerce platforms and enterprise-level applications.