Because written messages are generally shared, sometimes with millions of people, and frequently kept for long periods of time, writers need to be aware of what they are saying and how they are saying it.
Your purpose, as a writer, is based on your situation: what events have led up to your decision to write? What do you hope to accomplish by writing? Writing for yourself might include wanting to express yourself creatively, to record something you want to remember, or to process a difficult decision. Oftentimes, however, we write to communicate with others. Your purpose might be to give information or instructions, to persuade someone to agree with you, to provide entertainment or inspiration, and many other reasons. The content of a written message is its essential component. As a writer, you have to decide what to include and what to leave out.
The audience of a written message is the person or people who’ll read it. Suppose that you had to write a short message explaining why you missed a meeting. How would you adjust the message if you were writing this message to the following audiences:
Voice is the way you sound when you write your message. The words that you choose (diction) will convey a particular tone. Through the words you choose, you’ll indicate your feelings about your subject—and your attitude toward your audience. For example, you may sound courteous or abrupt, respectful or rude, funny or serious, sincere or sly.
Another aspect of voice is called style, which refers to the way you express your ideas. Some styles make use of informal language (slang, colloquialisms, contractions, personal pronouns [I/we], simple words, short sentences) while others make use of formal language (sophisticated vocabulary, long or complicated sentences, third person perspective).
Form or format refers to the way a message is organized and presented. Messages can be written in point form or in sentences and paragraphs. A written message could be sent as an e-mail or a letter, or it could be published as an editorial, an essay, or a report. Some types of messages, such as formal letters and reports, have specific formats that audiences expect to be followed. The best way to become familiar with expected formats is to read and look at a variety of examples.
When reading any text, take note of clues as to the author's purpose, intended audience, and chosen form. This will help you better understand the text's meaning and effect, and will help you when it comes time to write yourself.