Hair extensions are strands of synthetic or natural hair that can be added to a person's existing hair to create length, volume, or a different style. They come in various types, including clip-in, tape-in, and sew-in extensions, allowing for different application methods based on personal preference and desired results. These extensions can be made from human hair or synthetic fibers, with human hair often providing a more natural look and feel. Hair extensions are popular among individuals looking to change their hairstyle temporarily or enhance their appearance for special occasions.