Communication is the priority of business people and serves to promote services and products and to transfer information. Business communication determines business success and is very important for cooperation with business partners, clients and teamwork. Business could not be realized without communication either written or verbally, and the aim was to successfully mediate between the interviewees. Writing communication requires more knowledge and competence of that time and thinking to be successful. The precondition for a successful psychological and physical development of an individual is his relationship with others, as a guide for good interpersonal relationships and communication. Though communication is not only about speaking and understanding speech, it also refers to agreeing to certain gestures, mimicry and physical movements. People who are deprived of natural functions as hearing or speech and with bodily injuries as physical disabilities of communication are considerably more difficult. Communication is a social life. Throughout the work, the importance of communication through history and its development over the years will be reviewed. Standard Croatian language will be defined as an important link in communication and writing as well as styles used in writing and in everyday communication. Of particular importance is the administrative-business style of writing or writing business letters. Through the work, the content and rules of writing business letters, types and obligations will be defined and give examples.