The letter is written by an organization or a company in order to appoint an auditor firm to look after their audit. The letter follows a professional format to present every detail regarding the appointment. It is addressed to the chartered accounting departments of a company mentioning all the terms and conditions. The details mentioned by the company should be framed as per the provisions of the Companies ACT, 1956. The name of the charted account firm and its Reg. No. is mentioned along with the details in the letter. The time period and working area of the auditor firm should also be mentioned in the letter. To make the data authorized, the signature of the director of a respective company is needed.