As of 2019, PowerShell Core (aka PowerShell 6) is missing a lot of features (especially for AD and Exchange management). It is a separate install and it’s named pwsh.exe. It uses .NET Core.
Windows PowerShell is the original - found in C:\WINDOWS\System32\WindowsPowerShell\v1.0\powershell.exe it comes with Windows and has version 1.0 to 5.1. It is using the .NET Framework.
Powershell modules written in .NET Standard will work on both.
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