You can create a double click action which starts an editing command when the cursor is positioned over an object in a drawing and a double-click event is registered from a pointing device.
The Object Name property of a double click action must be a valid drawing interchange format (DXF™) name, or a special name for insert objects.
The CUIx file that ships with AutoCAD defines the default double click actions. You can use the default double click actions as examples when creating your own double click actions.