Office 365 comes with a dizzying array of subscription packages for Home, Business, Enterprise, Non-Profit, Government and Education.
Office 2019 is sold as a one-time purchase, which means you pay a single, up-front cost to obtain and use the Microsoft Office suite on one computer. One-time purchases are available for both PCs and Macs. However, there are no upgrade options. This means if you plan to upgrade to the next major release, you'll have to buy it at full price.