2013, the first version of Office 365

 
In 2013, Microsoft launched the first version of Office 365 when it launched Office 2013.
 
Office 365 is defined as a service, primarily a OneDrive.com-side service. At the same time, additional Office software is provided. Of course, the basic service does not provide Office desktop software, only the web version of the Office app.
 

2015, Office 365 includes Office 2013 and Office 2016

 
In 2015, Microsoft Office 2016 was released. As an excess, Office 365 offers both Office 2013 and Office 2016 downloads.
How and where to download and install 2013 version of Office 365?
 
 

2017, Office 365 was renamed Microsoft 365 and only Office 2016 is available

 
On January 4, 2017, Office 365 was renamed Microsoft 365. Only Office 2016 downloads are available.
 

2018, Microsoft 365 includes only Office 2019

 
On September 28, 2018, Office 2019 was released, and Microsoft 365 is only available for download of Office 2019.
 

2021, Microsoft 365 includes only Office 2021

 
On October 4, 2021, Office 2021 was released, and Microsoft 365 is only available for Office 2021 downloads.
 

Microsoft 365 doesn't necessarily include Office desktop software

 
Microsoft 365 doesn't necessarily include Office desktop software.
For example, Microsoft 365 Business Basic in the following image.
It only provides simple Web Office and Mobile Office apps.
Office software for Windows and Mac desktops is not available.

Office software for Windows and Mac desktops is not available for Microsoft 365 Business Basic.