Abstract One of the essential aspects of life is communication and in all communication systems, modulation and demodulation perform a crucial role in the transmission of transmitter-to-receiver data. Using various multiplexing techniques such as FDMA, CDMA and TDMA to work with the communication system, faced various problems such as low bit rate, multi-path fading, ISI and time dispersion. The incorporation of the OFDM approach gives an attractive solution to the aforementioned issues. OFDM transmitters and OFDM receivers with different modulation techniques are included in the OFDM-based different communication system. CO-OFDM was recently suggested and its extreme robustness against polarisation mode dispersion and chromatic dispersion was demonstrated in proof-of-concept transmission experiments. Optical fiber-based wired networks and also free space wireless networks require a premier technique for multiplexing i.e. CO-OFDM. In this paper, we investigated the performance of various modulation techniques which highlights several benefits such as channel robustness and greater efficiency of the available spectrum where multicarrier is used as high data rate bit streams from a single source are divided into the number of small subcarriers. OFDM is commonly regarded as discrete multitone (DMT) in this case. So in this review article, OFDM systems are also incorporated with their advantages and applications.