The process of formation of fossil fuels is

A hydrocarbon-containing substance that naturally formed in the earth's crust from the remains of extinct plants and animals is referred to as a fossil fuel. It is a substance that is removed and burned. The three most important fossil fuels are coal, crude oil, and natural gas. Fossil fuels can be utilised to generate energy, run engines (such as internal combustion motors found in automobiles), or provide heat for immediate use (such as cooking or heating). Some fossil fuels are treated before burning in order to create derivatives like kerosene, gasoline, and propane. Fossil fuels are derived from the anaerobic decomposition of buried dead animals that contained organic molecules created by photosynthesis. It frequently takes millions of years for the geological process to turn these materials into high-carbon fossil fuels.