Make sure the AzureADPreview module is loaded, you might have to remove the AzureAD one first.
# Get-AzureADPolicy
Get-AzureADPolicy : The term 'Get-AzureADPolicy' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included,
verify that the path is correct and try again.
# Remove-Module AzureAD
# Import-module AzureADPreview
# Get-AzureADPolicy
Id DisplayName Type IsOrganizationDefaul
-- ----------- ---- --------------------
c9755042-7b11-4504-b9e6-6347d0beabf5 B2BManagementPolicy B2BManagementPolicy True
29155710-2987-424a-a58f-3dd445aa5c60 B2BManagementPolicy2 B2BManagementPolicy False
Also, you CANNOT run this on Core/CloudShell, if that's what you're trying to do. The AzureAD module is only supported on Windows PowerShell.