Increasing of information flows cause the necessity of optimizing their quantity, structure and distribution. In order to eliminate the disadvantages inherent in information systems of electricity delivery enterprises for the processing of internal information, a methodical approach to optimizing document circulation on the basis of modeling with the help of Petri Nets is developed. This article presents a systematic methodology for modeling document circulation flows at enterprise. The constructed model allows to form the structure of the system and the processes taking place in it, to analyze the static state of the system of document circulation and the dynamics of information flows. Also, we described mathematical model of document circulation process, where the central place is occupied by identification and removing of duplicate documents and those that are not processed at each stage of their moving. At final stage we propose to distribute information flows due to specificity of division. For this we need to define and assign information functions to divisions and formalize them considering the rules for processing documents. To determine the extent to which the processing rules of the documents actually go in the subdivision of its main for each transition we introduce the measure of its specificity for subsystem.