Why An inductor stores energy in a magnetic field, and the easiest way to concentrate that field is to wind wire into a coil, often around an air, ferrite or iron core. Current through the turns creates the magnetic field, and the coil's opposition to changes in current is its inductance, measured in henries. So a coil of wire is literally the physical form of an inductor.
Watch out A capacitor is the other energy storage component, but it stores energy in an electric field between two plates separated by an insulator, not in a coil. Transistors and diodes are semiconductors, not wound wire.
Coil = inductor = magnetic field. Plates = capacitor = electric field.