Hi @Arpna • Thank you for reaching out.
Graph API can NOT be used to sync the identities from On-premises AD to Azure AD. Using Graph API, you can create/read/update/delete objects in Azure AD, but you cannot sync the objects using Graph.
To sync objects from On-premises AD to Azure AD, the recommended tool is Azure AD Connect. You can use it to sync Users, Groups and Computer objects but not OUs as Azure AD doesn't support the concept of OUs.
Read more: https://learn.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-install-express
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