Microsoft Azure Storage is a Microsoft-managed service that provides durable, scalable, and redundant storage. Microsoft takes care of maintenance and handles critical problems for you. An Azure subscription can host up to 100 storage accounts, each of which can hold 500 TB. If you have a business case, you can talk to the Azure Storage team and get approval for up to 250 storage accounts in a subscription.
Azure Storage consists of four data services: Blob storage, File storage, Table storage, and Queue storage. Blob storage supports both standard and premium storage, with premium storage using only SSDs for the fastest performance possible. Another new feature added in 2016 is cool storage, allowing you to store large amounts of rarely accessed data for a lower cost.
You can view your data objects using one of a number of storage explorers, each of which has different capabilities. For your convenience, Microsoft has a page listing several of these, including its own: https://azure.microsoft.com/documentation/articles/storage-explorers/. While you can view and update some data in the Azure portal, the customer experience is not complete. For example, you cannot upload blobs or add and view messages in a queue.
General-purpose storage accounts
There are two kinds of general-purpose storage accounts.
The most widely used storage accounts are Standard storage accounts, which can be used for all four types of data—blobs, files, tables, and queues. Standard storage accounts use magnetic media to store data.
Premium storage provides high-performance storage for page blobs and specifically virtual hard disks (VHDs). Premium storage accounts use SSD to store data. Microsoft recommends using Premium storage for all of your virtual machines (VMs).
Blob storage accounts
The Blob storage account is a specialized storage account used to store block blobs and append blobs. You can’t store page blobs in these account;, therefore, you can’t store VHD files. These accounts allow you to set an access tier to Hot or Cool; the tier can be changed at any time.
The hot access tier is used for files that are accessed frequently. For blobs stored in the hot access tier, you pay a higher cost for storing the blobs, but the cost for accessing the blobs is much lower.
The cool access tier is used for files that are accessed infrequently. For blobs stored in the cool access tier, you pay a higher cost for accessing the blobs, but the cost of storage is much lower.
Source of Information : Microsoft Azure Essentials Fundamentals of Azure Second Edition