As of this writing, it is still possible to purchase Word 2019 (to install on a single PC) as part of the Microsoft Office 2019 software suite.
Office Home & Business 2019 costs about $250, although Microsoft also offers a basic version for $150 called Office Home & Student 2019 that only includes “classic” Office apps for PCs and Macs-Word 2019, Excel 2019, and Power Point 2019.
The other way to get Word 2019 is to subscribe to Office 365. Instead of a one-time purchase, you pay a subscription every month or year. It includes Word 2019, Excel2019, and PowerPoint 2019, plus Outlook, OneDrive, and other software products and services.