Cant we use a PHP file directly like myhome.com/some.php?

I think you’re just looking for a basic php include:

include '/some.php';

Just make sure the path is correct. I’ve used this before no problem, php will interpret your included file as if it were part of the file including it.

… after reading your question again you may be asking for something even simpler, just link to your file from another page to access any resource, including php files, on your site.