The development of successful electronic procedures is a complex activity that requires diverse expertise on administrative processes and software development. Such expertise requires a multidisciplinary team that should combine technical issues and expectations of all users, including citizens and administrative clerks. This chapter is aimed to help you to understand how model-based approaches can be used to deal with development of complex e-procedures and, in particular, to communicate design options to a multidisciplinary team. To this very purpose this chapter illustrates two kinds of models: tasks models that describe the actions user should perform at every step of an administrative procedure; and system models that describe how design options can be implemented by the system to support user tasks. When used altogether, these models provide useful information to understand the implications of individual user's tasks and the system's behavior along the different steps in the underling workflow of an e-procedure.