And it also has a very good web version so you can easily browse the documentation even if you are not on your main work computer (from home, from a coleague's desktop or laptop). This is a feature I really on all the time actually.
IMHO MS has really step up their game in terms of the web versions of their apps. A couple of years ago we were still being force fed this clunky outlook web version that only worked properly in IE, and now we have popper functional cross browser web apps for everything.
Screenshot of One Note web interface: