StorageV2 is the newest type of storage account and it combines the V1 storage with Blob storage. It offers all the latest features such as access tiers for Blob storage with a reduction in costs. Microsoft recommends using this account type over the V1 and Blob storage account type.
V1 storage accounts can be upgraded to V2.
For more information on pricing and billing for these different account types, you can refer to the following pricing page: https://azure.microsoft.com/en-us/pricing/details/storage/.
