Answer and Explanation:
In an electric field generated between two electrodes there is a separation of charges: a negatively charged electrode called cathode and a positively charged electrode called anode. Ions are charged particles, so they can be positive or negative charges. Opposite charges attract each other. So, the cathode - negatively charged - attracts positively charged particles. On the other hand, the anode - positively charged - attracts negatively charged particles.
Therefore, positive ions move towards the cathode and negative ions move towards the anode.