PHP is a scripting language originally created for web development and now used as a general purpose programming language. Key developers include Rasmus Lerdorf and Zeev Suraski. PHP scripts can be embedded into HTML pages and is commonly used to connect web pages with backend databases. PHP is influenced by C and supports features like variables, functions, and object-oriented programming. It has a large standard library for tasks like string handling, dates, files, and working with databases.