Communication involves an exchange - of electrical signals, of sounds, words, pages of print, or whatever. Notice, for example, that each of the previous set of examples contained sender and a receiver and a message. The book was written by its author to be read by its audience. The video tape was produced by one group of people to be watched by another. And the invitation is a message sent from my sister to me.
Communication involves the creation, transmission, and reception of messages.
Although even very simple messages can convey meaning, many communication systems make use of organized, complex patterns of messages.