PHP scripts are pieces of code written in the PHP programming language, which is widely used for web development. These scripts allow developers to create dynamic web pages that can interact with databases, handle user input, and perform various server-side tasks. When a user requests a page, the server processes the PHP script and sends the resulting HTML to the user's browser. PHP scripts can be embedded directly into HTML files, making it easy to integrate dynamic content. They are executed on the server, meaning the user does not see the PHP code, only the output. This functionality makes PHP a popular choice for building websites and web applications.