This is fun.
First it was ClickOnce, where you can have setup program that updates itself when necessary on every run.
Now, VSTO beats document level macro.
Sample reference:
1. To create right click menu in Word in VSTO: https://msdn.microsoft.com/en-us/library/dd554969(v=vs.140).aspx
2. A thorough guide in VSTO and deployment: https://stackoverflow.com/questions/2081040/best-content-on-how-to-deploy-and-share-a-vsto-solution
3. Making MS Word Ribbon in VSTO: https://www.codeproject.com/Articles/192724/Justin-s-VSTO-Knowledge-Base-First-VSTO-Applica