What is current?

Free electrons are present in all conductors and semiconductors. When a potential difference is applied across any conductor, electrons in a conductor flow from the higher potential to the lower potential. This flow of electrons constitutes the current.
Simply speaking current is nothing but the flow of electrons in a conductor.
Current can also be considered as the rate at which the charge moves through the conductor, measured at any particular point

I = V / R

 V = potential difference across the conductor.
R = resistance offered by the conductor to the flow of current.