What are the signs given to the electrodes in both the voltaic and electrolytic cells? What reaction (oxidation or reduction) is occurring at each?

In a voltaic cell, electrons flow from the anode to the cathode. Anode is negative while cathode is positive.

In an electrolytic cell, electron flows from the cathode to the anode. Anode is positive and cathode is negative.

For both, Oxidation occurs at the anode and Reduction occurs at the cathode.