Aside from the fact that they have totally opposite effects on the current in a circuit, capacitors and inductors are two totally different but equally important components of modern electronics.
An inductor is nothing more than a coil of wire, with as few as two loops up to hundreds of loops wrapped around a core. The core can be empty (“air core”) or some manner of material that tends to support the creation of magnetic force lines (high permeability, para- or ferromagnetic, I don’t remember all the terms, but iron is common and very effective at making magnetic fields).
A Capacitor is a bit more complicated and consists of two thin sheets of conductive material (usually some kind of foil) separated by an insulating material (dielectric) that may be paper, mica, plastic, rubber, even air.
Inductors react to and oppose changes in current, capacitors react to and oppose changes in voltage (if I have that backward, somebody please correct me). When current is applied to an inductor, a magnetic field is generated, oriented according to how the coils of the inductor are wound. As the current in the inductor increases, the magnetic field gets stronger and it generates a magnetic force that induces current that would be opposed to the current that created the field.
That’s not nearly as elegant as the textbook explanation, but the point is that the inductor opposes current that is applied to it.
When the voltage is applied to a capacitor, the current is blocked by the insulating layer between the conductive sheets, creating an electrostatic field that stores electrical energy proportional to the voltage that was applied. When the applied voltage cuts off, the electrostatic energy stored in the insulator is released in the form of opposing “negative” voltage (positive and negative with voltage are relative terms used to give a reference and direction, if the negative voltage were applied to the capacitor, the stored voltage would be positive).
Both components store energy in their own way, and that stored energy is the basis of everything mankind has been able to accomplish with electricity: Inductors are the basis of electromagnetics, electrical generators, motors and even speakers, while capacitors are used in communications devices and computers (made even more effective and efficient with transistors and other semiconductor-based devices, but I understand those even less and won’t even try to explain them to another reader).