PHP is an open-source general-purpose scripting language that is especially suited for server-side web development. At first, PHP stood for Personal Home Page, but now it is the recursive acronym for PHP: Hypertext Preprocessor.

Like JavaScript, PHP can be embedded into HTML but instead of running on the website client-side, the code is executed on the server. It generates HTML which is then sent to the user. It can be used on all major operating systems and deployed on most of the web servers used.

PHP can, among other things, generate dynamic page content, manage files, handle forms, access cookies, control user access, and encrypt data. It can also be used for command-line scripting and for writing desktop applications (though it is not the best language for the latter).
According to W3Techs, PHP is used by 79.1% of all websites whose server-side programming language is known (as of March 2021). Websites that use PHP include Facebook, WordPress, Moodle, Wikipedia, and Zoom. The newest version of PHP is 8.0 which was released in November 2020. Most websites use version 7 or even version 5.