👉 A mailer is a type of promotional material that is used to send out advertising or promotional information. These materials can be sent through email, postal mail, or other means of communication. The main purpose of mailers is to reach potential customers and gather their contact information. They are often used by businesses to promote new products, services, or promotions to a wider audience. Mailers can be designed in various formats, such as postcards, brochures, newsletters, or direct mail pieces.