Microsoft Office is a pay once, receive once service, but there are deals available for both Microsoft Office and Microsoft 365 membership.
For Microsoft Office, packages like Home & Student 2021 offer apps like Word, Excel, and PowerPoint.
For Microsoft 365, there are good deals for Business Basic, Business Standard, and Business Premium memberships.
The primary difference between Microsoft 365 and Microsoft Office is that the former is a subscription service, while the latter is a one-time purchase.