Choose and change user settings in QML

[DiegOne]

Good afternoon QT Forum,

my goal today is to set user application settings in QML using Qt.application.name.
I have an application that starts in a page where the user can select its profile name/settings clicking on a button. At this point at button click the application starts with some users specific settings. The doc file ( https://doc.qt.io/qt-5/qml-qt-labs-settings-settings.html#:~:text=%23include <QGuiApplication> %23include,Qt.application.domain. ) states that the specific setting can also be controlled in QML via : Qt.application.name, Qt.application.organization, Qt.application.domain.
However this command is not working for me. My code is simply:

onClicked{
Qt.application.name("myUserName")
}

I don't even have the .name property listed in the available properties of Qt.application

Could you help me explaining where I am wrong? Thanks