There hasn't been an official printed manual for Word for many years, but the Quick Start guide Desiree pointed you to will get you started. Other Microsoft (and third-party) articles cover many other specific Word features, both in Word 2016 and in other
versions. If you want a paper reference, there is usually a good selection of third-party guides (search Amazon or your local bookstore), though my experience has been that, while they are a good introduction to Word's features (especially new features in
a given version), they rarely answer the esoteric questions I tend to have. For that, this forum is a better bet.
The article at https://wordmvp.com/FAQs/General/WheresTheManual.htm explains why there's no longer a paper manual. When it was written, most of the detailed information about Word was still in the built-in Help. Since then, Help has mainly been moved to the Web, making
it difficult to find assistance when you are offline, but there is a huge amount of information available when you are online. In my experience, you will have better results searching with Google than searching within Word (using Bing).