Instruments and necessary methods for correspondence and the use of special emblems to confirm and ratify the authenticity of documents issued by rulers has been a major element of administrative procedures in various periods of history. For the same reason, since the advent of Islam such methods and systems came to be a centerpiece of attention as well. In his correspondences with the leaders and emperors of the period, the Prophet of Islam (S), also, evidently used his ring as a seal to officially endorse and ratify such letters. With the passage of time, the methods of writing and the ways of correspondence and posting of adminstrative letters have been subject to change in various periods of history. The purpose of this paper is to conduct an etymological study of words and expressions such as tamgha, toghra, and yarligh and explain their historical trend and development in the administrative systems of the Islamic Period.