Biochar (BC), a carbon-rich material derived from biomass through thermal combustion in an oxygen-limited environment, offers a versatile solution with various applications. Biomass waste sources suitable for biochar production encompass agricultural crop residues, forestry waste, municipal solid waste, and animal manures. The distinctive characteristics of biochar, including its large surface area, high porosity, functional groups, and cation exchange capacity, render it suitable for diverse applications. Notably, the pyrolysis method significantly influences biochar yield, with slow pyrolysis yielding 30% more charcoal compared to fast pyrolysis or gasification methods. Biochar has garnered considerable attention for its efficacy in removing contaminants, particularly heavy metals, from wastewater, offering a cost-effective and environmentally friendly solution. However, the original biochar's capacity for heavy metal sorption is limited. This review discusses various feedstock materials and production methods for biochar, spanning traditional and modern techniques. Furthermore, the potential application of nanomodified biochar for the removal of toxic heavy metals from wastewater is explored, highlighting future prospects for sustainable environmental remediation.