@MohdRizv@MohdRizvi89 The Hierarchy is Management groups ==> Subscription ==> Resouces groups ==> Resources. Subscriptions are always added under the Management groups either at root level if you don't have any or it will be created if you have sub management groups. the purpose is management groups is to provide governance and apply polices When you add a new subscription you are creating a logical patriation under that management groups maybe one for development, prod When you are moving the subscription it is more of cut and paste you are moving to another management group which means subscription can participate on one management group only
Ref this URL for more detailed explanation
Organize and manage multiple Azure subscriptions - Cloud Adoption Framework | Microsoft Learn
Azure Subscription Best Practices: A comprehensive guide to effective cloud governance - Motifworks
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