To ensure that the members of Group1 can upload files by using the Azure portal, they need to have both data access and management access to the storage account. Data access refers to the ability to read, write, or delete blob data in the storage account. Management access refers to the ability to view the storage account resources in the Azure portal, but not modify them. The Azure role-based access control (Azure RBAC) system provides built-in roles that encompass common sets of permissions for data access and management access. The Storage Blob Data Contributor role grants read, write, and delete access to blob data in the storage account. The Reader role grants view access to the storage account resources in the Azure portal. Therefore, by assigning both roles to Group1, the members of the group can upload files by using the Azure portal. This solution also follows the principle of least privilege, as the group members are only granted the minimum permissions required to perform the task. Reference:
Assign an Azure role for access to blob data
Data access from the Azure portal