Orthogonal  Frequency Division Multiplexing  is considered as one of the most promising technology for future communication technology as it provides spectral efficiency robustness against multipath fading & avoids inter symbol interference. However one of the major drawbacks of OFDM system is high PAPR resulting in performance degradation of DAC & decreases efficiency of power amplifier. In this paper we review on OFDM system, its different types of PAPR  reduction techniques and comparison of different PAPR reduction techniques