Parchment paper sheet is basically paper that has been coated with silicone. It can come in bleached or unbleached varieties, and the silicone makes the paper non-stick and heat-resistant, as well as water-resistant.
Parchment paper is like the anti-mess weapon of the kitchen, and it makes for easy clean-up in many different ways. For added convenience, you can even buy parchment paper that is already pre-cut into sizes that you need.
This makes it extremely versatile, so it is great for baking projects, layering in between desserts and candies, covering your workspace as you do messy things.