Create Azure Policy Assignment using Azure PowerShell

create-policy.ps1

# Login to Azure Subscription
Login-AzureRmAccount

# Get a reference to the resource group
$rg = Get-AzureRmResourceGroup -Name "az-policy-rg"

# Get a referecen to the Azure Policy Definition
$policyDef = Get-AzureRmPolicyDefinition | Where-Object { $_.Properties.DisplayName -eq "Audit VMs that do not use managed disks" }

# Create the new Policy Assignment for the Resource Group
New-AzureRmPolicyAssignment -Name "Check for Managerd Disks" -DisplayName "Check for Managed Disks" -Scope $rg.ResourceId -PolicyDefinition $policyDef