Quantum computing is a facet of computing with a focus on developing computer technology based on quantum theory. Quantum theory itself explains how energy and material behave on the atomic and subatomic levels.
Traditional computers that we currently use are only able to encode information in bits with the value of 1 or 0. This significantly restricts their ability.
Conversely, Quantum computing utilised quantum bits, often referred to as qubits. A qubit is the basic unit of information in a quantum computer. It has something like a particle or an electron that adopts two possible states, and while it is in superposition the quantum computer and specially built algorithms use the power of both these states. This allows quantum computers to handle operations at speeds exponentially higher than regular computers all the while consuming significantly less energy.