Created by Rasmus Lerdorf in 1994 and publicly released June 8, 1995, PHP, which is short for PHP: Hypertext Preprocessor, is a server-side interpreted scripting language. It was designed for creating dynamic web pages and web pages that effectively work with databases. Below are two examples of how you'd print "Hello World" using PHP in a .php file.
<? print("Hello World!") ?>
<? echo 'Hello world'; ?>