how does a step down transformer alter the amount of voltage from a power line to a building?

A step-down transformer reduces the voltage from a power line to a building by utilizing two coils of wire, known as the primary and secondary windings. The primary winding receives high voltage from the power line, while the secondary winding, with fewer turns of wire, produces a lower voltage output. This transformation allows for safe distribution of electricity within the building, ensuring that appliances and systems operate efficiently at the required voltage levels.