How is coal formed step by step?

Coal is formed through a process called coalification, which occurs over millions of years. It begins with the accumulation of plant material in swampy areas, where dead plants are buried under sediment. As layers of soil and rock build up, heat and pressure transform the plant material into peat, and eventually into different types of coal (lignite, bituminous, and anthracite) through chemical and physical changes. This process involves the loss of moisture and volatile compounds, leading to the formation of carbon-rich coal.