The formal letter is one of the three letter-types in the GT IELTS Writing Task 1 test. When you are required to write a formal letter, begin it with "Dear Sir or Madam", use formal expressions and end the letter by signing off using "Yours faithfully". Do not exchange personal greetings at the beginning of the letter and do not use contractions (for example, don't, I'd etc.) while writing a formal letter. You usually write a formal letter to a person whom you do not personally know.