AzureDomainTransfer.ps1

$ResourceLocation = "Global"
$ResourceGroup = "RESOURCE GROUP"
$ResourceName = "DOMAIN NAME"
$PropertiesObject = @{
    'Consent' = @{
        'AgreementKeys' = @("DNPA","DNTA");
        'AgreedBy' = 'IP ADDRESS';
        'AgreedAt' = '2017-04-23T04:07:00.0000000Z';
    };
    'authCode' = 'AUTH CODE';
    'Privacy' = 'true';
    'autoRenew' = 'true';
}

# May need this first - sometimes the powershell provider isn't loaded.
Register-AzureRmResourceProvider -ProviderNamespace "Microsoft.DomainRegistration"

New-AzResource -ResourceName $ResourceName -Location $ResourceLocation -PropertyObject $PropertiesObject -ResourceGroupName $ResourceGroup -ResourceType Microsoft.DomainRegistration/domains -ApiVersion 2015-02-01 -Verbose 

Powershell script to transfer a domain into Azure.

Original, one modification to add the resource provider.
https://social.msdn.microsoft.com/Forums/azure/en-US/271731d8-6cd2-443b-b861-ee4ee30e34e9/transfer-domain-registration-to-azure