CmdID / PowerShell / Cmdlets / Get
Get-ExchangeServerAccessLicenseUser
Use the Get-ExchangeServerAccessLicenseUser cmdlet to return a list of unique users for the specified license name. Exchange PowerShell reference
From the Exchange PowerShell reference 1 parameter Its page in the reference
Parameters
-LicenseNameThe LicenseName parameter specifies the license type that you want to view.