Posters are used for a variety of purposes, and as such fall into types or classifications that make it easier to create a poster because each type has its own particular features.
Advertising posters are everywhere and are used to announce an event or a new product, according to the Free Library website. They are usually full-color and placed in high traffic areas, where they can be readily seen.
These types of posters do just what it seems like they should do—inform or educate people about something. They might be used for a social awareness campaign or to help save an endangered species.
Subject posters are about something. They are sold at concerts or at art functions typically. The portrait of a musician or an art exhibit are often the subjects of these posters, hence the name.
Affirmation posters feature inspiring or motivational sayings. They can feature Bible verses or beautiful pictures, plus some sort of affirming slogan to keep people motivated, cheered up or comforted.
Propaganda posters often receive negative press because they are very often associated with political campaigns or corporate communication. They often feature logos and portray the values or philosophy of a company or political candidate.