Digital transformation in Industry 4.0 today is associated with the transition to cyber-physical systems through the use of digital twin technologies, the industrial Internet, Big Data, Artificial Intelligence, Machine Learning, etc. In this work, an attempt of strict theory developing was made that would allow to determine, “what Digital Twin is” and to determine the place of the Digital Twin among other models. As a result, a cyber-physical Cross-Domain Model of Communication Service Provider and the model of the Digital Twin for the digital service provider was suggested. The models aim to meet new problems in communications management.