Quantum fields are fundamental entities in physics that describe how particles interact and exist in space and time. According to quantum field theory, every type of particle, such as electrons or photons, corresponds to a specific field that permeates the universe. These fields can fluctuate, creating particles when energy is added, and can also be thought of as the underlying fabric of reality. In this framework, particles are seen as excitations or disturbances in their respective fields. For example, the electron field gives rise to electrons, while the photon field produces photons. This concept helps explain various phenomena in particle physics and is essential for understanding the behavior of matter and energy at the smallest scales.