What are the basic functions of communication?

The basic function of animal, including human, communication is the exchange of ideas; the transmission of messages:

Person A has an idea they want to convey to Person B, and they convey this idea by gestures, facial expressions, sounds (including spoken Words), signals (including writing), and so on: it's all communication, whether it's 'Hi, Fred,' television news, or a twelve-volume reference work.

The exchange of ideas takes place between different species, such as humans and animals, as well as the exchange of ideas between members of the same species.