There are several types of doors, each designed for specific purposes. Common types include hinged doors, which swing open and closed on hinges, and sliding doors, which move horizontally along a track. Bi-fold doors consist of multiple panels that fold to one side, while French doors feature two hinged doors that open outward, often used to connect indoor and outdoor spaces. Another category is security doors, designed to provide enhanced protection, often made of metal. Pocket doors slide into a wall cavity, saving space, while barn doors offer a rustic look and slide on a track. Each type serves unique functional and aesthetic needs.