Human development is defined as the process of enlarging people's freedoms and opportunities to improve their well-being, emphasizing the importance of real choices and capabilities. It includes biological and psychological growth throughout the lifespan and is influenced by income, education, and health, which are key factors in a country's development. The Human Development Index (HDI) offers a composite measure of well-being based on health, education, and income, shifting focus from mere economic growth to the quality of life and improving opportunities for all.