@sarvesh chaudhari Thank you for reaching out to us, As I understand you are trying to creating a Device on AAD/Entra Using Microsoft Graph API.
As far I know, Device registration service calls Microsoft Graph to create device when device registration is triggered. This can be for Entra registered/Entra joined/Entra Hybrid joined device states.
The only scenario where non device registration service calls create device is Intune when they create synthetic devices. A device which is not directly registered to Entra ID but registered via another service say Defender is called synthetic device - https://learn.microsoft.com/en-us/mem/intune/protect/mde-security-integration#environment
In short, its not possible to create a device id via Microsoft Graph manually, Refer to this for more details - Device registration process
Let me know if you have any further questions, feel free to post back.
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