Absolutely, one of the big points with a customer portal is to give the customer access to efficient tools where they aren't dependent on your assistance. The idea is that the customer portal provides an omni approach to customer care, which means that routines are the same regardless of how they are initiated.
In Bizzjoiner's case management you can both let the customer's users create their own cases or you can create them for them. Regardless, all cases that are linked to the customer are available for effective communication where all of your employees and all the customer's users have access to the same information.
Similar questions
Can we customize what kind of cases the customer can use?
Can users be notified when something changes in a case?