Formal letters have a specific structure and format. They are used for professional communication regarding work concerns, orders, applications and addressing problems. A formal letter includes the sender's address, date, recipient's address, salutation, subject, body organized in paragraphs, complimentary close and signature. The body should be brief, clear, precise and polite. Common complimentary closes are "Yours sincerely" or "Yours faithfully". Formal letters follow a block, modified block or semi-block format to organize the elements in a clear, readable way.