To install the module for SharePoint PnP, Your PowerShell engine version must be greater than 4.0.
You can use the below command to determine the current version of your PowerShell Engine.
$PSVersionTable.PSVersion
It will shows the major , minor, Builder and revision number.
If your major version is less than 4.0 , then you need to upgrade it to next major version.
You can download and install the "Windows Management Framework 5", link
https://www.microsoft.com/en-us/download/details.aspx?id=50395
In my case, I am using the Windows 2008 R2 SP1 and selected the relevant installation file from download page
Win7AndW2K8R2-KB3134760-x64.msu
Once you upgraded to next version, you need to install the Module for "SharePoint PnP PowerShell Online."
Post upgrade , I can install the SharePoint PnP PowerShell for Online.
