Set font weight and size for Label
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Panel title="My Application" paddingTop="10" paddingBottom="10" paddingLeft="10" paddingRight="10"> <mx:Label text="Hello World!" fontWeight="bold" fontSize="24" /> </mx:Panel> </mx:Application>