There is no such facility in Word.
However, she could use the comment feature for each purpose and save that version with a new but related name. I.e.
Project - name given base document
Project - design notes - name given copy for designer
Project - organizer notes - name given to copy for assistant

An alternative method would be to use different character styles for in-text notes. Those styles could be different colors of text and could be formatted as hidden. She could modify the style to not-hidden for the one being sent. If a Word document is being sent, though, she should be aware that hidden text is still in the document and could be viewed by someone who has their computer set to view hidden text. (I generally keep such text displayed all the time on my systems.)
Showing non-printing formatting marks in Microsoft Word