Narratives are accounts of past events, either real or fictional. A narrative essay, which tells about real incidents, must have a clearly defined setting, characters, plot and point of view. It must include an introduction, a climax and a conclusion. The author's purpose in writing a narrative essay is to communicate an important lesson learned during the story -- such as the importance of knowing how to swim when the author nearly drowned -- and not just recount past events.
The purpose of an expository text is to give information about a specific topic. It is not storytelling, but a straightforward discussion of a topic, such as population increase in New England, the reasons behind it and its effects. According to Professor Arnetha F. Ball of Stanford University, the author of an expository text cannot assume that the reader has prior knowledge of the topic; therefore, the writer must use plain language and an easy-to-follow structure.
The author of a technical text also has the purpose of explaining a specific topic, but a technical text's language and structure distinguish it from other expository types. A technical text contains specific terminology to address the text's issues and avoids colloquial terms, humor and critical language. In addition, vague terms and figurative language have no place in a technical text, in which authors use few, if any, interrogative sentences -- sentences that are questions and imperative sentences -- sentences that are commands.
The author of persuasive text tries to convince the audience of the validity of the author's opinion. This type of text can employ a number of different persuasive methods. These techniques include the use of rhetorical questions, repetition, emotive language, exaggeration, addressing the readers directly and using facts as a means of backing up a point. The writer must mention the issue clearly and must express an opinion on it explicitly.