A sticker is a type of label: a piece of printed paper, plastic, vinyl, or other material with pressure sensitive adhesive on one side. They can be used for decoration or for functional purposes, depending on the situation.
Stickers are very widely used when an object requires with a word or idea. Brand stickers may be attached to products to label these products as coming from a certain company. They may also be used to describe characteristics of the products that would not be obvious from simple examination. A label dispenser is often used as a convenient way to separate the sticky label from its liner or backing tape.