Mitosis and meiosis both involve cells dividing to make new cells. This makes them both vital processes for the existence of living things that reproduce sexually. Meiosis makes the cells needed for sexual reproduction to occur, and mitosis replicates non-sex cells needed for growth and development.
Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. Meiosis creates new combinations of genetic material in each of the four daughter cells. That is why meiosis results in greater genetic diversity than mitosis.