Wave Function Theory is a fundamental concept in quantum mechanics that describes the quantum state of a particle or system. It represents the probabilities of finding a particle in various positions and states, encapsulated in a mathematical function known as the wave function. This function evolves over time according to the Schrödinger equation, allowing physicists to predict how particles behave at the quantum level. The wave function is typically denoted by the Greek letter Ψ (psi) and contains all the information about a quantum system. When measured, the wave function collapses to a specific value, giving a definite outcome. This theory is essential for understanding phenomena such as quantum superposition and entanglement, which challenge classical intuitions about particles and their behavior.