Office 365 is a Microsoft subscription service.
The Office 365 Service provides a complete set of Windows Office installation packages.
The Office installation package belongs to Click-to-run office.
The Windows Office installation package provided by Office 365 is divided into 2013 and 2016 versions.
Of course, after you subscribe to Office 365, you can use these 2013, 2016 versions at the same time.
(Of course, Microsoft may no longer provide the old version of the download, such as: Office 365 of the 2013 version)