Hi umit ceylan,
Thank you for reaching out to us on the Microsoft Q&A forum.
Based on your description, you have a domain controller VM connected to Entra ID using Microsoft Entra Connect with a custom domain.
You also have several virtual machines that are domain-joined to your domain controller. Now, you want to transition these devices to be joined to Entra ID.
To enroll these VMs into Entra ID, you need to configure them for Microsoft Entra Hybrid Join. This requires setting up Microsoft Entra Hybrid Join on Microsoft Entra Connect, which will configure a Service Connection Point (SCP).
Once the devices are synced to Azure, their join type will change to Microsoft Entra Hybrid Joined, allowing you to log in to these VMs using your on-premises user accounts.
Please refer to the following guide for detailed steps on configuring Microsoft Entra Hybrid Join:
https://learn.microsoft.com/en-us/entra/identity/devices/how-to-hybrid-join
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