Hello,
I'd say that both word try to define similar entities, but with different perspectives and precision.
use case is a word that comes from the UML world (Unified modeling language). It corresponds to the specification of a scenario that users of your system should be able to follow.
The fact that a user could come to your website and choose to delete an invoice, along with the result page showing the success of this operation, could be described in a use case.
Defining use cases at the beginning of a project helps to understand how the system should be modeled, what are the important scenarios of interactions between the components.
workflow is a word that comes form the world of process automation, and process reverse-engeneering. What are the actors, their roles, and the sequence of actions that they need to perform in order to accomplish a given task.
If you can describe your worflow (there actually exist so-called workflow languages, you will be able to use a workflow engine to distribute the tasks among the actors and follow the status of each task.
Insurance companies typically use workflows to monitor the insurance claims they receive. It is important for them to have such a monitoring because they have an obligation to answer to all claims.
In your case, you could say for instance
- That 2 use cases have that webpage as a starting point
- That 2 worflows may be accomplished via this webpage
I hope this will be of some help to you
Jerome WAGNER