Dry food is generally made by extrusion cooking under high heat and pressure. It may then be sprayed with fat to increase palatability and other ingredients to complete its composition.
Pet owners often prefer dry cat food due to the convenience and price. Besides usually being significantly cheaper, dry cat food can also be left out for the cat to eat at will over the course of several days; whereas, canned or raw cat food spoils or becomes unappetizing after several hours.
Dry food is recommended by some based on the idea that cats break apart dry foods with their teeth, which causes the food to scrape off dental calculus. The degree of benefit this provides has been disputed in recent years.