The use of renewable energy sources like biomass for producing daily products like hydrocarbon fuels with comparable properties is a promising future energy pathway. Lignin is one of the main biomass components usually generated by the paper industry as a low-value byproduct. Instead of on-site burning, lignin can be upcycled to solid, liquid, and gaseous biofuels by torrefaction, pyrolysis, and gasification, respectively. This work explores the chemical structure and isolation methods of lignin, providing a comprehensive understanding of its conversion processes. Likewise, various lignin conversion routes aimed at producing biooil, syngas, H2, and fuel pellets, respectively, are thoroughly discussed. Following this, future directions and main conclusions are provided. Overall, this chapter offers a comprehensive overview of the application and production of renewable energy in the form of solid, liquid, and gas from lignin. This could provide valuable knowledge and information for fostering a decarbonized and sustainable society.