How to find root directory of the website run on a port of localhost?

I am running an website on address: 10.207.218.213:8089 so now i want to add a comment.php file to sent data input from input textbox to mysql database but i can not find this directory to copy it. Please show me how to fid it. Special thanks

I tried to copy this file to xampp/htdocs but it not working, browser still notify it can not find this file. When i click submit button, the browser say: Not Found The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.