You may create exact copies of the selected document(s) of a specific document type.  

To change the Document group 1 or 2 on documents: 

  1. On Documents (Documents list screen) (Default ribbon), select the Document type, if the correct document type for sales documents (i.e. Invoices, Credit notes or Quotes) or purchase documents (i.e. Purchases, Supplier returns or Orders).
  2. Select the Document(s), right-click on Documents → Copy document on the context menu. Exact unposted copies of the selected documents will be created for the same document type.

If you need to select multiple documents, press the Ctrl or Shift key and click on each document, which you need to copy.

Once this is done, you may edit / post these documents.

Once a document is copied, the selected source document fro which it is copied, will be added to the third message line. 

You need to edit the first and second message line if required. 

Note the Document message (set in the Setup → Documents setup on the Setup ribbon) will also be added to the copied message of the selected source document.