Ironing gives clothes a smooth, pressed look.
Linen usually requires very high temperatures; cotton requires a hot iron, but not as hot as linen. "Permanent press" clothes, in theory, don't require ironing, but when you do iron them, it's usually one of the lower settings. Polyester and some other synthetic fibers should be ironed on relatively cool settings, and can potentially melt, if they get too hot. To high or hot of a setting can damage a cloth's finish, so some clothing suggests you iron it turned inside out with the iron touching the side of the fabric that doesn't show when you wear it.
Many people avoid ironing by using clothing that doesn't need it, hanging clothes up before they're completely dry or clothing that is intended to have a "wrinkled" look.
As with other electrical appliances that get hot, there are some safety precautions. Keep in mind...
- make sure the cord is no frayed
- irons can tip over and heat things that should not be heated or start fires, so hot or heating irons should be attended
- ironing boards are often not very stable and can easily be tipped over by children or pets playing or bumping into their legs
- irons get very hot, so even a quick touch on the heated surface can cause bad burns
- About.com's housekeeping section on 7 Ironing Mistakes and How to Avoid Them
- Wikipedia's article on ironing
- TLC chanel's Ironing Tips