What are the main Azure storage types and when would you use each?

Azure Storage account services:

• Blob Storage — unstructured objects: images, backups, logs, video, data lake files. Tiered as Hot, Cool, Cold, and Archive, with progressively lower storage cost and higher access cost. Lifecycle policies move data between tiers automatically.
• File Storage — fully managed SMB and NFS shares. Its main use is lift-and-shift, where an application expects a mounted network drive.
• Queue Storage — simple message queuing for decoupling components. Service Bus is the richer alternative when you need ordering, sessions, or topics.
• Table Storage — a basic key-value NoSQL store; Cosmos DB is the modern successor.

Managed Disks are separate — block storage attached to virtual machines, in Standard HDD, Standard SSD, Premium SSD, and Ultra Disk tiers.

Databases are a different question again: Azure SQL Database for relational, Cosmos DB for globally distributed NoSQL, and managed PostgreSQL or MySQL where you want the open-source engine.

Note: Redundancy options are a likely follow-up. LRS keeps three copies in one datacentre, ZRS spreads them across availability zones, GRS replicates to the paired region, and GZRS combines both. The cost rises with each step, so match it to how bad losing the data would actually be.