PHP (Hypertext Preprocessor) is a programming language primarily used for creating dynamic web pages. It is typically used on the server-side (server-side scripting) to create web pages that are generated in response to a user's request. PHP is widely used because it is easy to learn and use, and it is supported by a large community of developers. MySQL is a popular database management system (DBMS) used for storing and retrieving data. It is used to store and manage data for websites, applications, and more. MySQL is a popular choice because it is easy to use, affordable, and has a large support community.