php is basically a framework to handle server requests before presenting that information on a webpage. if your site has a database, for example, php is used to call information from that db before sending it along with your HTML request.
if you’re looking for a php file, open the folder and make sure you can see extensions associated with that filetype. for a php file you would look for something like some_random_file_name.php.
open a php file up in a text editor. you can also edit it from cpanel. use ctrl+f to locate the specific line of text that you are looking for. make sure to save.
i am learning php too. thanks for the chance to share what i’ve (gulp) learned. good luck to you.