PHP (PHP: Hypertext Preprocessor) is a widely-used open-source programming language that runs on a webserver. It’s the most popular server-side script language used today and all WordPress sites run on PHP.
The lifecycle of the PHP version is about 2 years from its official release (plus 1 year of additional support), after which they are no longer supported. After they lose support, the PHP version needs to be updated.
The main benefits of PHP version update are improved security, new features and improvements and faster websites.