Communication between two or more people is called

Communication between two or more people, exchanging messages face to face or through a shared channel, is interpersonal communication.

It builds and sustains relationships through direct give and take between sender and receiver.

Communication confined within one organisation's formal hierarchy describes organisational communication, a narrower workplace setting rather than any two people.

Contact with a non-human or an imagined external agent belongs to extrapersonal communication, which is not person to person.

The silent self-talk that happens inside a single mind is intrapersonal communication, involving only one participant.

The dyad, two people in exchange, is the smallest and most basic unit of interpersonal communication.