 We developed a systematic framework for categorizing quantum circuits according to their qubit functional configurations. This classification allows us to identify common features among different types of quantum circuits, such as complexity or hardware efficiency. We applied our framework to variational quantum algorithms, which are efficient methods for solving certain problems. By identifying the functional configuration of these algorithms, we were able to understand how they work and how to optimize them for specific tasks. This article was authored by Sishu Anhu and Saber Kais.