Managed disks automatically handle storage account creation for you. With unmanaged disks, which are the traditional disks used for VMs, you need to create a storage account manually, and then select that storage account when you create the VM. With managed disks, this burden is handled for you by Azure. You select the disk type and the performance tier (standard or premium), and the managed disk is created. It also handles scaling automatically for you.
Managed disks are recommended by Microsoft over unmanaged disks.
Now that we have covered all of the background information that you need to know about the different storage accounts, we are going to create a new storage account.