Stardraw applications do not include a 'cloud' tool, but you can create this type of object using the Bezier tool.
Alternatively you could use an existing cloud object using Object Linking and Embedding (OLE). For instance, if you have a cloud saved as a JPG you can insert the JPG file into your drawing - select Edit | Insert New Object, then choose Create from File and browse to the file you want - you can then overlay text onto the object.
For more on OLE see Stardraw's help system, go to the Index and select "Insert New Object"
The third option would be to use a cloud if you have it saved as a file type that Stardraw can open directly, e.g. .DWG. Just open the file and save it as a Stardraw symbol (drag it into the Library List under My Libraries) for repeated future use.
I hope this is helpful
Kind regards
Rob