Well, they are the same thing used for different purposes.
With the voltaic cell you are converting chemical energy into electrical energy as in a battery.
With the electrolytic cell you are applying electrical energy to cause a chemical change. Often that allows a chemical reaction to move in the opposite direction than what would happen in a voltaic cell.
With the voltaic cell you are converting chemical energy into electrical energy as in a battery.
With the electrolytic cell you are applying electrical energy to cause a chemical change. Often that allows a chemical reaction to move in the opposite direction than what would happen in a voltaic cell.