HTTP, or Hypertext Transfer Protocol, is the foundation of data communication on the World Wide Web. It enables the transfer of hypertext documents, allowing users to access and interact with web pages through their browsers. When a user enters a URL, their browser sends an HTTP request to the server hosting the website. The server then responds with the requested content, which can include text, images, and multimedia. This request-response model is essential for the functioning of the internet, making HTTP a crucial protocol for web development.