With Microsoft 365 subscription plans, you get the full version of Office applications: Word, Excel, PowerPoint, OneNote, Outlook, Publisher and Access (Publisher and Access are only available for PC). You can install Microsoft 365 on various devices, including 5 PCs and Macs, 5 Android smartphones and tablets, iPads and iPhones. Plus, with Microsoft 365, you get services like online storage with OneDrive and Skype minutes for home use. If you have an active Microsoft 365 subscription, you will always have the most up-to-date version of Office applications.
Office as a one-time purchase includes applications such as Word, Excel and PowerPoint for use on a single PC or Mac. Applications do not update automatically: to get the latest version, you must buy Office again when the new version is available. In addition, Office as a one-off purchase does not include any of the services included in Microsoft 365.