Insoles provide many benefits to users, such as cushioning, comfort, support, alignment, pain relief, and injury prevention. These benefits relate to design and material selection. Each layer of insoles has a specific role and function in footwear. There are many materials for insoles, including soft materials, rigid materials, and moisture-wicking materials. Materials of each part of the insole play an important role in footwear function related to the material’s properties. The diabetic insole provides support, cushioning, and pressure offloading to minimize the risk of injury. The soft insole materials had better performance than the rigid insole materials during plantar pressure offloading. There are several manufacturing techniques for insole fabrication, including conventional fabrication, digitalized manufacturing, subtractive manufacturing, and additive manufacturing. Digitalized and additive manufacturing techniques are increasingly effective in terms of labor utilization, waste management, and time efficiency. Furthermore, using artificial intelligence in the insole design and customization can enhance more personalization, efficiency, and effectiveness, which are benefits to customers and patients.