A primer is a cosmetic product applied to the skin before foundation or other makeup. Its primary purpose is to create a smooth base, helping makeup adhere better and last longer. Primers can also help minimize the appearance of pores, fine lines, and uneven skin texture, providing a more polished look. There are various types of primers available, including those designed for specific skin types, such as oily, dry, or combination skin. Some primers contain additional benefits, like hydration or oil control, while others may include SPF for sun protection. Choosing the right primer can enhance the overall makeup application and finish.