The voltage needed for electrolysis of water does not depend on the electrode area (see Nernst equation for the calculation of the minimal theoretical voltage needed). Actual voltage will be larger depending on the resistance of the electrolyte, the separation between electrodes and the electrode materials.

For estimation of the current and the relationship between current and number of moles of hydrogen generated, please read about Faraday laws of electrolysis.

Thank you Dr. Fernando for your helpful answer