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If I understand correctly, you would like to copy all the IAM permission roles on all resources of tenant and assign the same roles to same user in another tenant.
Currently, there is no feature to transfer the roles from one tenant to another tenant. If you move a resource that has an Azure role assigned directly to the resource, the role assignment isn't moved and becomes orphaned. After the move, you must re-create the role assignment. Eventually, the orphaned role assignment is automatically removed, but we recommend removing the role assignment before the move.
However, you can Download role assignments of your resources and use the list of role assignments in new tenant.
Reference: Move Azure resources to a new resource group or subscription
List Azure role assignments using the Azure portal
Assign Azure roles using the Azure portal
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Thanks,
Akhilesh V.
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