This review comprehensively describes biochar, the term which is gaining exponential attention nowadays. The technologies to convert the agriculture waste to biochar include slow pyrolysis, flash pyrolysis, and hydrothermal carbonization. Biochar production methods are based on batch processes and continuous processes. Biochar production processes and steps involved are also discussed. Different biochar reactors are also revived, including the continuous type of biochar reactor and microwave pyrolysis reactors. Kinetics of biochar, bio-oil, and syngas production is also revived briefly with kinetic equations. Uses of biochar are comprehensively revived and discussed, including advanced applications such as catalyst production, activated Carbon production, water treatment, soil amendment, etc. All biochar characterization methods are briefly described, including proximate analysis, ultimate analysis, physiochemical analysis, surface analysis, and molecular structure analysis. Factors affecting biochar production are revived in this article. Biochar yield from different crop waste s is tabulated with temperatures involved. Post-production processing methods of biochar are included in this review. The global biochar market and current status and opportunities are also revived, the data of biochar manufacturers in India are compiled. The utilization of biochar in agriculture is revived in two subcategories: the effect of biochar application on soil health and the effect of biochar application on crop yield. At last engineered or designed biochar concept is revived.