You told me you couldn't find the file...
did you locate it?
If so, remove "phpmyadmin|"
THEN (provided you have set up port forwarding and your XAMPP install is already accessiable friom the web)
everyone in the world will be able to run your phpMyAdmin as if they owned the server (becasue they do)
you do something to secure phpMyAdmin:
Possibilities - a .htaccess file in phpMyAdmin, secure the phpMyAdmin by changing config.inc.php AND no matter what - change the MySQL root password.
there's a built-in page for changing the MySQL/phpMyAdmin parthttp://localhost/security
(read it) then go to http://localhost/security/xamppsecurity.php