Soaps are made from fatty acids reacting with alkalis like sodium hydroxide or potassium hydroxide. There are two main types: hard soaps that use sodium salts and are moderately soluble, and soft soaps that use potassium salts and are very soluble and form lather easily. Soaps are made through heating fats/oils with alkalis in a process called saponification, and various materials like perfumes, dyes, and fillers are added for different applications. The manufacturing can be done through batch processes or continuously. Final products include bar soaps, liquids, flakes, and more.