When writing a letter, you must provide the intended recipient's address as well as your return address. A personal letter will normally include three lines: the recipient's name, their street address, and their city, state, and zip code. If you do not know the exact address, you can use a mailing service such as UPS or USPS to send your letter. They will usually give you form letters that you can copy and use for different addresses. In addition to the required information, letters contain several other elements: a greeting (a short sentence that expresses your appreciation for the recipient's business), a body that discusses the issue at hand, and a closing (which is an expression of gratitude or farewell). Greeting and closing forms are provided in most correspondence courses. Body forms require you to provide space for two paragraphs to explain your position on the issue at hand or to describe some experience or event that relates to the topic. The first thing to do when writing a letter is to decide what kind of letter it will be. You can write a formal letter if you want a very polite message delivered in full view of others. An informal letter is sent from one friend to another and is used to share secrets or talk about someone who has done you wrong.