The mechanical operation performed to break down the coffee bean and increase the surface area that comes into contact with water, making it easier for the water to extract the aromatic substances.
Coffee can be ground using manual or electric grinders. The latter, usually found in coffee shops, generally have flat or conical burrs, and can be volumetric (with a doser that fills with ground coffee and then empties gradually as the barista makes the coffees) or on demand (capable of grinding the dose of coffee required for each extraction).

The latter are certainly preferable if the quality of the extraction is a priority, because they ensure a more consistent, fresher grind, thus making it possible to preserve the characteristics of the coffee such as acidity
and sweetness.