How to Add a Button to Word

I have a program that opens a Word document or creates it if it doesn't exist.

How can I add code to my program that will create a Button in that Word document ?

I would like the Button to be in the Quick Access Toolbar if that is possible, else I can put it at the end of the Home Tab.

I know I can do Customise the QAT within Word & create a VBA program to do what I want, but that will then be there for ALL Word documents that I use, and I don't want that because one of the functions of the Button, will be to create an E:Mail with the document attached.