You can specify the widgets available to users (Dashboard), group administrators, blog administrators, and site-wide by modifying the widget availability list in the Control Panel.
To locate configurable prepackaged widgets, navigate to Control Panel Dashboard > System Administration > Site Administration > Widget Studio > Enable/disable widgets.
You can move widgets between the unavailable and available lists. The site-wide widgets are available on all site pages. The dashboard, groups and blogs widgets override the site-wide widgets, meaning that for dashboard, groups and blogs the widgets available to users are the ones specified in those lists.