A window sign is a visual display, typically made of paper, plastic, or vinyl, that is placed on or inside a window to convey a message or advertise a product or service. These signs can range from simple text and graphics to elaborate designs and can be found in a variety of settings, such as storefronts, offices, and vehicles. They are often used to attract attention, promote sales, or provide information to passersby. Window signs are a popular and effective form of advertising, as they are eye-catching, cost-effective, and easily customizable.