An author's purpose is defined as the reason an author creates a piece of writing. Authors have three major reasons for writing something: to persuade, to inform or to entertain. Teachers often use the acronym PIE to help students remember these reasons.
An author uses persuasive writing to entice readers to agree with her way of thinking. Examples of persuasive writing include editorials, advertisements, cover letters and most political writing.
An author uses informative writing to convey facts about a subject to her readers. Examples of informative writing include textbooks, instructions, reference texts and news stories.
An author uses entertaining writing to captivate her readers. Examples of entertainment writing include poems, stories, song lyrics and screenplays.