You shouldn't do it this way.

There must be just one profile.php, serving all users. That's the way how PHP works. It is used to create dynamical sites, producing dynamical content based on user's input.

So, based on entered username, it should display particular user's info. One script to serve all users.

The PHP copy() function just copies a file from one directory to another.

http://php.net/manual/en/function.copy.php

As Col. Shrapnel suggest, you shouldn't copy the profile.php for each user. That will be hard to maintain, and unnecessary duplication. But here's how you can make subdirectories for each of your users.

<?php

    $username = 'me';

    if(userregisters) {
    mkdir('/file/to/path/{$username}');
    }