Information theory has been crucial to develop modern digital communications. As quantum computing is evolving and getting increasing attention, the development of communication between quantum devices appears as a natural consequence. Researchers around the world have defined quantum versions of classical information theory concepts and explored their differences. Not only the community has foundnew version of the classical concepts, but has also defined many new concept that arise from the laws of quantum mechanics--- and so have no classical analogous. In this work, we present two main topics: a study of the evolution of quantum entropies during a decoherence process and the analysis of entanglement fidelity for different quantum channels acting on one qubit messages,both in a general case and a concrete example.