Every widget has a handle you can click for opening its menu, and for moving the widget via drag-and-drop. Using this menu, you can have the widget properties displayed (if it has any) or edit them in editing mode. In addition to the property views built into the Web Builder, further ones can be provided by a website developer, e.g., for extended styling options.
The menu also lets you delete a widget or duplicate it. Note that the latter does not duplicate referenced content, e.g. images. So, after duplicating an image widget, you’ll have two of them displaying the same image object.