Your purpose, or reason for writing, helps you select and arrange information; it sets a standard for measuring your final draft. Most likely you will want to create a certain response in your readers.
DISCOVERY CHECKLIST
Do you want to inform — announce something, update others, explain some specialized knowledge, or reply to a request?
Do you want to motivate some action — get a question answered, a wrong corrected, a decision made, or a personnel director to hire you?
When your readers are finished reading what you’ve written, what do you want them to think? What do you want them to do?