Please see the list of available actions that come with install4j.
Actions are attached to screens or they are part of the startup sequence that allows you to perform actions before the installer or uninstaller is displayed. If any of these actions fails and has a "Quit on failure" failure strategy, the installer application will not be shown.
Some actions have an "affinity" to a particular screen and will suggest to add themselves to that screen, such as the actions in the "Final options" category which would like to go to the "Finish" screen. However, this is only a suggestion to guide you for the most common use case.
Some actions have an associated screen that allows the user to modify the behavior of the action. For example, the "Install a service" action has a corresponding "Services" screen that allows the user to decide whether the service should be installed and started on bootup. If such a relationship exists, a corresponding notification is displayed after adding an action.