The article is concerned with the study of comparing and contrasting different features of formal and informal letters. Letters are a form of verbal and written communication, which contains information or message, send by one party to another, to convey the message. It is sent by one party to another, to provide certain important information. There are two types of letters, i.e. formal letters and informal letters. The formal letter is written for business or professional purposes with a specific objective in mind. Previous researches and studies in this area of investigation have been gathered and analyzed. Several points of the issue have been taken into consideration and concluded that there are distinctive differences between formla and informal letters.