Quick Access Panel: 
Ribbon: Editor -> Draw -> Cloud
The Cloud tool allows adding a revision cloud to the drawing. Revision clouds represent closed polylines in the form of clouds that consist of arc segments.
While working with the drawing, you can use the Cloud tool to highlight a particular drawing part.
Go to CADEditorX
URL of this topic:
https://it.cadsofttools.com/help/cadeditorx/index.html?cloud.htm