PHP is a server-side scripting language designed specifically for the web. Within an HTML page, you can embed PHP code that will be executed each time the page is visited. Your PHP code is interpreted at the web server and generates HTML or other output that the visitor will see.
PHP was conceived in 1994 and was originally the work of one man, Rasmus Lerdorf. It was adopted by other talented people and has gone through several major rewrites to bring us the broad, mature product we see today. According to Google’s Greg Michillie in May 2013, PHP ran more than three quarters of the world’s websites, and that number had grown to over 82% by July 2016
PHP is an open-source project, which means you have access to the source code and have the freedom to use, alter, and redistribute it.
PHP originally stood for Personal Home Page but was changed in line with the GNU recursive naming convention (GNU = Gnu’s Not Unix) and now stands for PHP Hypertext Preprocessor.