QAction* myAction = new QAction("My Action", this); // this refers to the parent object QFont myFont("Arial", 14); // create an instance of QFont for Arial font with size 14 myAction->setFont(myFont); // set the font of the label for the actionIn this example, the setFont() function is called on a QAction object named myAction. A QFont object named myFont is created beforehand, which specifies the desired font (Arial) and size (14). The font of the label for the action is set to this font by calling setFont() with the QFont object. Package/Library: The setFont() function is part of the QAction class, which is defined in the Qt Core library. Therefore, to use this function, you need to have the Qt framework installed in your development environment.