Hi @찬혁 박
Azure Resource Manager is one of the backbones of Azure itself.
When you deploy any kind of resource (VM, etc) it must pass through ARM.
You may have heard of ARM templates? That’s a json representation of one or more resources which you can deploy through Azure Resource Manager.
More here:
overview
An Azure Management groups work at a level above your Azure subscription.
It helps you control multiple subscriptions all under 1 or more ‘umbrellas’ known as Management Groups.
If you don’t have multiple subscriptions then you likely have no use for Management Groups.
More here:
overview