When it comes to programming languages, you will notice that a majority of developers are pretty comfortable with using PHP. This is because it allows them to focus on just one area at one time. Also, PHP is an open-source programming language, so it is also free.
PHP is a core server-side programming language for the web. It powers the majority of WordPress. PHP helps in doing some really important functions like saving content to a database, reading content from a database, writing loops and conditional statements, pulling in files like images, and pulling in WordPress specific information.