Quantum electrodynamics is a quantum field theory that describes the interactions between light and matter, specifically focusing on electromagnetism. It is one of the most precisely tested theories in all of physics, successfully modeling phenomena ranging from atomic energy levels to the scattering of high-energy particles. Within the framework of the theory, the electromagnetic force is mediated by the exchange of virtual photons. The theory provides a quantitative description of how charged particles interact with the quantized electromagnetic field, offering predictions that align remarkably well with experimental results.