Prefold diapers are rectangular layers of fabric sewn together in thirds. The middle has more layers than the two sides. Prefolds can come in sized or one-size. They can be made from many different fabrics including cotton (Birdseye or Indian), hemp, or terry. With cotton prefolds you can find either bleached or unbleached cotton. Chinese prefolds are simply prefolds that are made in China.
To use a prefold diaper, you can either fold the diaper using a diaper fold secured with a Snappi or diaper pin. My favorite, and the easiest way to use a prefold is to fold it in thirds and lay it inside a cover. Prefold diapers do not contain a waterproof outer layer, so you will need sometime of waterproof diaper cover.