You can continue to renew and purchase new software licenses, Software Assurance, and online services through the Open License program until December 31, 2021. As of January 1, 2022, commercial customers won’t be able to buy new or renew software licenses or online services through the Microsoft Open License program. New license-only purchases should be transacted through partners in the Cloud Solution Provider program. Read more
Office 365 is the name of a special subscription service that allows the use of familiar server and desktop products from Microsoft. The word "Office" refers to the functionality of the products. The figure "365" means that products are available 24/7.
Server products are hosted on servers in Microsoft. Desktop applications (if included in plan) are placed on users' devices. Setting up and using server products is done via the Internet. Distributions of desktop applications are downloaded from the Microsoft website.
There are several sets of server and desktop applications called "plans" (Office 365 Plans comparison). Annually purchased licenses provide the right to use the products included in the "plans". More information about licensing of cloud products is available on the Microsoft website.