Go to a specific Customer Hub and, on the right hand-side, you will see "Workflows".
It shows you the workflows the customer is currently enrolled in, as well as:
Name of the workflow
Date when they joined this workflow
Date when the last action was taken by the workflow
The Current node is it at, as well as whether it is pending action by the user (you) before continuing.
If you are looking to understand the previous workflow enrolments, have a look here.