DIDs support multiple storage mechanisms. Each storage mechanism defines how to create, read, write/update, and delete DIDs. Here's a list of the already implemented and published mechanisms: https://w3c.github.io/did-spec-registries/#did-methods. They range from no storage (e.g. did:key, you derive the DID from a public key but can't change/update anything about that DID) to stored on a webserver (e.g. did:web) to stored on a blockchain (e.g. did:ethr).

Often, a DID is created from a public/private key pair that is used to sign a transaction that's specific to the DID method. The DID then becomes publicly visible with the associated configuration, e.g. multiple key pairs associated with the DID, service endpoints that allow an interaction with the DID, etc.

Look into sidetree protocol, I've seen a lot of people building on top of it.

Link: https://identity.foundation/sidetree/spec/