availability-groupssql serverwindows
For setting up Always On Availability Groups in SQL Server I know you need to have at least Enterprise Edition for SQL Server 2012, 2014, or 2016.
Do you also need the Datacenter or Enterprise Edition of Windows Server 2012 or 2016 for Always on, or can you set this up properly on Windows Server Standard 2012 or 2016?
Always On is not synonymous with (Always On) Availability Groups and instead is more a marketing term to describe a suite of Microsoft High Availability technologies (which I argue is at best ambiguous). The term actually started out as "Always On" (note the space) a long time ago 
as a pure marketing term (see my graphic as an example), but with the release of SQL Server 2012 was adopted as a wider catch all replacement marketing name for what they called "Hadron" during development (which was specifically Availability Groups) and several other HADR technologies (such as SQL Failover Clustering). The only difference was that when the term was first used, it did not have the trailing space (i.e. "AlwaysOn"). Marketing in their infinite wisdom have now added a space back into the term to add even more confusion :).
The bottom line is that if you completely ignore the use of the term AlwaysOn/ Always On and explicitly refer to the technology Availability Groups/ Failover Clustering/ Database Mirroring etc (or ask people to clarify which technology they are referring to) then you cannot go far wrong.
Do you have an MSDN License? Or could you start a 30-day free trial with Azure? If so, you can easily set up a VM with SQL Server 2016 Standard edition installed:
This will help ensure no surprises with this or other Enterprise features.
Best Answer
Windows Server Standard Edition is fine.
Starting with Windows Server 2012 every feature of Windows Server is available in Standard Edition. In particular Standard Edition supports Windows Server Failover Clustering which is needed for some Always On capabilities.