A poster is a large sheet that is displayed either on a public space to promote something or on a wall as decoration. Nonetheless, the main function of a poster is to capture a moving audience with a message. Typically, posters include both textual and graphic elements. Posters are designed to be both eye-catching and informative. When designing a poster, determine the most important information and the imagery that will best convey your message visually because you only have a short amount of time to attract and hold your readers attention.