The need to achieve increasingly better performance in present and future tokamak devices has made plasma control increasingly important in tokamak engineering. When high performance and robustness are required, it is essential to adopt a model-based approach to design a control system. We introduce the basics of plasma current, position, and shape control in tokamaks. As an example, the plasma magnetic control systems of the JET tokamak is presented, together with an approach proposed for plasma axisymmetric magnetic control at the ITER tokamak.