If your customers have QlikView you can send them the QVW file, but usually you would upload your QVW file to a server that has QlikView Server installed and users would enter in a portal called QlikView AccessPoint that allows them to view your QlikView file through an Internet browser using AJAX or the IE Plugin. To do all this you will need to purchase a proper license
Converting QlikView to Exe is not available to the general public.
Mireille, you would have to add a fixed public IP to the QlikView Server so that users can access it from outside. Often you don't want external users to access the same server as internal users, so you might think about setting up another server. This probably depends on the region, but QlikView even offers a Extranet server license for this purpose.