Classic Storage accounts - Created by using an existing Service Management API's (Existing REST API Stack).
Are you interested in learning Azure from basics! Here's the right video for you on Azure provided by Intellipaat:
The Newer Storage Accounts - They are created with the New Azure resource manager (ARM) API's, these are wrapped in PowerShell and CLI as of now.
They both provide the same resources to your application, but their creation and management are quite different- likeability to tag the resources created using ARM Scripts.
You cannot convert any classic into a newer type.