Cell to cell communication occurs through three main processes: exocytosis, endocytosis, and cell junctions. Exocytosis exports materials from the cell via secretory vesicles, while endocytosis imports materials through phagocytosis, pinocytosis, or receptor-mediated endocytosis. Cell junctions like tight junctions, gap junctions, and desmosomes allow communication between cells through physical connections or cytoplasmic channels.