Transfer sticker is a sticker with three individual pieces, which consists of the backing paper, the transparent film, and the sticker itself. These three parts will stay together in actual products.
When you "transfer" them to a window or other surface, you should remove the backing paper first, then stick to other surfaces. After several times of pressing, tear off the transparent film and transfer it to other surfaces completely. The transfer sticker generally cuts the sticker material into shapes, graphics or text, and then removes the background.