Tone is the quality of writing that reveals your attitude toward your topic and your readers. If you show readers that you respect them, they are far more likely to view you and your message favorably. Most workplace writing today ranges from the informal to the slightly formal. Gone are extremely formal phrases such as enclosed herewith, or pursuant to the stated request. At the other extreme, slang, or a casual, overly friendly style might cast doubts on your credibility. Strive for a relaxed and conversational style, using simple sentences and familiar words.
Observe business etiquette in courteous writing. If you have a complaint, recall that your reader may not have caused the problem — and courtesy is more likely than sarcasm or insults to motivate help. When delivering bad news, remember that your reader may interpret a bureaucratic response as unsympathetic. And if you have made a mistake, acknowledge it.