The destructive impact of fading environments and also bandwidth limitations are two main challenges which communication is dealing with them. These challenges can affect on the growth of wireless communication and even cause reliable communications and high data rate to be prevented. Thus, OFDM (Orthogonal Frequency Division Multiplexing) modulation by using of fast calculation hardwares such as FFT, high ability for combating multipath fading and appropriate spectral efficiency has taken into consideration. However, we should know that OFDM systems potentially have high Peak to Average Power Ratio (PAPR). This drawback drives the power amplifier into saturation leading to higher distortions and also degrades BER performance. Since increasing the dynamic range of power amplifier is not affordable, reduction of the PAPR is so important. In this paper, we investigate the PAPR and its reduction methods by using the theoretical and numerical analysis. These techniques can be classified into two main categories, signal distortion techniques, multiple signaling and probabilistic techniques. The advantages and disadvantages of each technique are derived from different prospectives. Moreover, we compare the numerical results of the techniques in the first classification from BER prospective which demonstrates that for changing the parameters corresponding to each technique, its performance can be changed greatly. Hence, we are sure that a technique can not outperform the other ones in all cases. Finally, the computational complexity of the techniques in the second classification are compared to each other which their results show that TR and TI techniques are much more complex than the other ones.