Since the electric potential energy of two charges q1 and q2 placed at a distance r from
eachother is given by = (1/4 ??0) (q1 q2 /r)
Whether the electric potential energy of the two charges, on increasing their separation, will increase or decrease, it will depend upon the polarity of the charges. The electric potential energy will decrease in case of same polarity charges and it will increase in case of opposite polarity charges.