Anaerobic digestion (AD) is the preferred and promising method used worldwide to manage specific wastes and waste biomass. The techniques to maximize biogas productions by anaerobic digestion is explicitly introduced to achieve potential reactor operations. An essential consideration for combining anaerobic digestion with biochar is formed from waste biomass by thermochemical conversion. The latest enhancement work is showing the potential biochar results of augmentation of certain chemicals such as biofuels and charcoal, bioethanol, biodiesel, butanol, hydrogen, carboxylic acids, and hydrocarbons. However, there is still a lack of a detailed and robust interpretation of BC and AD relations. This article aims for systematic reviews on anaerobic digestion efficacy with the use of biochar. The maximum methane generation using biochar with enhanced AD efficiency ranges from 650 to 900 mL/d, with organic removal efficiencies varying from 70% to 75%. The major components of the biochar usage include hydrolysis, acidogenesis-acetogenesis, and the progression and equilibrium of methanogenesis are reviewed. Biochar properties provide reasonable conditions for pH adjusting, disinfectant, complementary sourcing, electron carrier servers, and the expression of physicochemical weights on an organism through various bacterial communities. Biochar can improve biomethane yield plans for the most part by chemically moving organisms, methanogen for biomethane yield, growth of microbial groups, and a stimulus for buffer potential. This article is giving an in-depth discussion of current advances, distinctive difficulties, and limitations of biochar applications in anaerobic digestion. Future research can focus on biochar's functions in acid buffering, acid reduction, and increasing syntropy between hydrolysis and acidogenesis-acetogenesis.