Fashion models promote clothing and accessories to fashion buyers and customers.
The commercial model is the silent salesperson promoting everything else.

Female fashion models should be somewhere between 15 and 22 years old, although probably closer to fifteen. Models don't have careers that last as long as for instance, doctors, so agencies tend to invest their time in someone young.

You should be tall, long-legged, and lean. The minimum height is usually about 5'8", and average weight for a model is 108-125 lbs. These characteristics are partly aesthetic and partly practical: this type of frame looks good on the runway and in front of the camera; and a somewhat scrawny build drapes clothing nicely and ensures a good fit in the standard wardrobe. There are always exceptions to the rule, of course - Kate Moss is 5'7" and Gabrielle Reece is a giant 6'3" - but, in general, the closer you are to the industry norm, the better your chances.

Fashion models still tend to be very skinny. Commercial modeling doesn't require that you be "skinny". The key is to take care of yourself. Don't overeat, but do eat well balanced meals and avoid the snacks. Exercise and keep yourself in good shape.

Male fashion models are normally 6' to 6' 2" tall and wear a size 40 regular jacket. Commercial models do not have any height, weight or size restrictions.