These reference architectures show options for integrating your on-premises Active Directory (AD) environment with an Azure network. Which should I choose?
Integrate with Azure Active Directory
Integrate on-premises Active Directory domains and forests with Azure AD.
Extend AD DS to Azure
Extend your Active Directory environment to Azure using Active Directory Domain Services.
Create an AD DS forest in Azure
Create a separate AD domain in Azure that is trusted by domains in your on-premises forest.
Extend AD FS to Azure
Use Active Directory Federation Services for federated authentication and authorization in Azure.