Packaging an application for a Linux distribution is a bumpy road. Because each distribution can have its own packaging format (.deb, .rpm, and so on), the first question to answer is which distribution do you wish to target? Covering every major packaging format would take several chapters. Even detailing a single distribution could be unfair (you wanted to package for RHEL? Too bad—we only covered Arch Linux!). After all, from a Qt application developer's perspective, what you want is to ship your product to your users; you are not (yet) aiming to become an official Debian repository maintainer.
With all this in mind, we decided to focus on a tool that packages the application for you for each distribution. That is right: You do not need to learn the internals of Debian or Red Hat! We will still explain the common principles...