Dear student,
Electric current is defined as rate of flow of charge.
in simple words, electric current is nothing but flow of charged particles in a circuit. By the term charged particles, we can denote any negatively charged particles (such as electrons and negative ions) or positive charge carriers (such as protons, positive ions or holes).
In case of metallic conductor, the charged carriers ere electrons, whereas in case of electrolyte, the charge carriers are positive and negative ions, and in case of semiconductor, the charge carriers are both electrons and holes.
Regards,