Elsa enables you to correlate workflows with a application-specific values. These values can be anything, but typically represent an identifier of an entity in your domain.
For example, it could represent a customer, a document, a change request, and anything else.
When to use correlation?
Imagine you have a document approval workflow that requests reviews of a document from users in the system. Such workflows are typically long-running: they will suspend while awaiting input from a user.
When a user provides input, the application needs to know which workflow instance to send the input to. That's where correlation comes in: the system sends input as well as the document ID.
See the Correlation Guide to see correlation in action.