Coffee filters are thin, porous papers or materials used to separate coffee grounds from brewed coffee. They are placed in a coffee maker or a pour-over device, allowing hot water to pass through while trapping the grounds. This process results in a smooth and flavorful cup of coffee. There are different types of coffee filters, including paper, metal, and cloth. Paper filters are disposable and come in various sizes, while metal filters are reusable and can provide a richer taste. Cloth filters are also reusable and can be washed, making them an eco-friendly option for coffee enthusiasts.