Azure controls access to resources, such as storage and queues, using role-based access control or RBAC. An Azure AD security principle, which can be a user, a group, an application service principle, or a managed identity for Azure resources, can be granted access to resources at the level of subscription, resource group, storage account or an individual container or queue. Before assigning to a user or group, you need to determine the scope of access required. It is best to allow only the absolutely necessary scope of access to resources. 

Starting with the narrowest, the levels of scope are:

An individual container: at this scope, a role assignment applies to all of the blobs in the container as well as container properties and metadata. 

An individual queue: at this scope, a role assignment applies to messages in the queue as well as queue properties and metadata. 

The storage account: at this scope, a role assignment applies to all containers and their blobs or to all queues and their messages. 

The resource group: at this scope, a role assignment applies to all of the containers or queues, and all of the storage accounts in the resource group.

The subscription: at this scope, a role assignment applies to all of the containers or queues, and all of the storage accounts and all the resource groups in the subscription.

To assign role-based access control to a storage account, select the storage account, then select Access control and click the Add button under Add a role assignment. Within Add role assignment, select a role from the drop-down list, then select the user or group you want to assign the role to, then click Save. If you go into Role Assignments, you can view what roles are being assigned to users.