There are a variety of different doors that are manufactured all for different purposes.
A single door is the most basic of doors, allowing entry from one room into another. Depending on its use it can have openings for glass so you are able to see through to the other side, or it could be solid where vision is not needed. They can be manufactured to be elagant and decorative to suit the clients choice or style.
French doors are 2 adjacent doors that have glass panes (commonly known as lights) that are hinged on opposite sides of the door, so that they can be opened from the middle. These are commmonly used to open otwards to a terrace, garden, porch or balcony. The framework may also have fixed panels or doors adjoining to the french doors where the frame needs to be larger and keep the characteristics.
Byfold doors is a series of doors that fold together in pairs, allowing a full opening from one side of the frame to the other. Every door is known as a 'leaf', a bifold is a door that slides open while its attached doors fold up and stack neatly against the wall.
A sliding door is a door that opens horizontally, usually sliding parrallel to the wall. These doors can either be suspended on a track above or set into a track below. A sliding door is usually a single unit made up of two panel sections. One bieng set securely and the other bieng able to slide open. Another design is called a 'pocket door' which consists of one or more moveable panels that slide directly into the wall pockets entirely vanishing. Giving a great open, indoor - outdoor exsperience.