This is a great question.
I doubt that the entire document can be copied to the clipboard once you have made the changes as the changes that are made are stored in temporary versions of the document so that, when you exit, for example, and press
Save, then the changes from the temporary file overwrite the current version of the file; if you choose to not save, then this temporary file will be discarded.
Here is my unsaved file:
And here is the temporary file; you have probably noticed these kind of files before but never paid them much attention (most people don't):
What this file does is stores/retains any changes and then, depending on your decision as to whether or not you want to save, will either apply the changes to the previous version of the document or discard them respectively. Effectively, whenever you work on a new document or update an existing one, the changes that you make are, in fact, made to a temporary file and are only applied if you choose to save them.
In this example, the text that you can see present in the Word document has not been saved yet and this is why the temporary (faded) file is present as these changes are saved in there.
The point I am making is that the changes you make will not exist unless you save them somewhere; basically, if it isn't saved, then the document will remain the same.
"But, pray tell, surely I could just send the temporary file in an e-mail?", I hear you ask.
Yes, you CAN send it via e-mail.
But the file won't work.
Here is what happens when you try to open the e-mailed temporary file:
The reason for this you may find surprising, which is the same as above: because the changes aren't saved anywhere, then there is nothing saved to send.
The only possible way would be to write your own custom script/software to achieve this, which is fine but in my opinion counter-intuitive as it might be quicker to simply create a default folder which is specifically for documents that you change and wish to send on.
Then all you would have to do is to immediately save the received document(s) to this location, make the changes, save, drag the updated document(s) into the blank message window within your e-mail client, send the e-mail and then clear the contents of the folder once complete, ready for next time. Maybe even leave this folder open in the background at all times so that it is always accessible.
This is what I would do personally.