The name iron comes from the actual metal that the appliance is made from. The shape of the iron, pointed at its end, allows you to iron all the corners of the clothes, while its weight smoothes the fabric.

The part of the iron that makes direct contact with the fabric is called the "sole (plate)". In order for the iron to be effective, then the device needs to be heated. This iron also makes use of a steam system, which makes it possible to humidify the fabric during the ironing process.

Ironing helps loosen the bonds between the long chains of molecules that make up polymer fiber materials. The heat and weight of the iron stretches the fibers while the fabric retains its new shape once it's cooled. Some materials, like cotton, require the use of water to loosen intermolecular bonds.

Information about steam irons

Information (2) on steam irons

Wikipedia link - Clothes iron