Having entered the world of PHP knowingly, you also stepped into the world of web programming as PHP is a popular web programming language too. An application written in PHP will have to be executed in either of the two mediums.
You need a web server such as Apache with the PHP module installed. If you need a web server, you are probably creating a web-based application that will run on a web browser.
To run PHP code, you need to learn just a shortcut Ctrl + Shift + F10. The rest is taken care of by PhpStorm.
The code will be executed according to the configuration you set. For more details about executing PHP code, you can refer to the previous chapter as well.
However, if you have no prior experience in executing PHP code in PhpStorm and you are not in the mood to try out something new, you can resort to old-school methods.