You get the premium Office software with the Office 365 subscription plans:
Word, Excel, PowerPoint, OneNote, Outlook, Publisher, and Access (Publisher and
Access are only available on a PC). Office 365 can be enabled across various
devices, including PCs, Macs, Android tablets, Android phones, iPad ®, and
iPhone ®. Office 365 also comes with services such as 1 TB OneDrive room, 60 Skype minutes
a month and support for Microsoft chat and phone. You get the new versions of
the software with a subscription, and also receive updates as they happen.
Learn more about Office 365.
Office 2019 is a one-time purchase that includes classic PC or Mac applications
such as Word, Excel and PowerPoint, and does not contain any of the features
that come with an Office 365 subscription. One-time purchases do not have an
upgrade option, which means you would need to buy it at full price if you intend
to upgrade to the next major update.