Descriptive writing, sometimes called "showing writing" is writing that describes a particular person, place or event in great detail. Descriptive writing uses a lot of flowery adjectives and adverbs to describe what is going on or how something appears. If you were going to describe biting into an apple, you would not simply say: "He bit into the apple and it tasted good". Descriptive writing would convey the same sentence as follows: "He slowly closed his teeth on the ripe, succulent, ruby colored apple. The crunch of his teeth piercing the apple's skin was deafening and the sweet juices of the apple ran down his chin. The taste of the meat was as sweet as candy and he felt euphoric."
A good example of descriptive writing in modern literature is the Hobbit series by J. R. R. Tolkien.