Block Storage: data is stored in chunks, on a volume attached on a single instance.

Very low latency data access and it is comparable to an Hard drive, where you can create volumes and partitions.

File Storage: data is stored as files in directories, within a file system. Think of a Network Attached Storage Server NAS - it has its own Block Storage system but it shares the file system over the network to multiple users and it can be mounted and when mounted you can't create volumes or partitions.

Object Storage: data is stored as objects in a flat address space and referenced by a unique key.

Metadata to help categorize and identify the objects can be associated. You can mimic a file hierarchy using folders structure, but it is just by using prefix - it is no real structure