Creating a custom url when navigating to a custom module form
There are multiple ways. 


You could use hook_menu() to declare a new path with the same callback (while still leaving the old one intact).
You could use Redirect module.
You could create a .htaccess redirect. (A 301 redirect is the proper way to do it if you want the new one to permanently replace the old one.)
You could create a new Path Alias.