This thorough review explores multiple present-day multiverse theories along with their special theoretical underpinnings and different empirical predictions, in addition to multiple potential implications for basic physics. We assess how well Boltzmann, Quantum, and M-theory frameworks, which are multiple multiverse models, explain cosmological fine-tuning, vacuum state dynamics, and quantum decoherence. The paper combines several recent improvements in observational cosmology, high-energy particle physics, and quantum gravity. This combination is done to evaluate the evidentiary support for multiverse hypotheses. Possible observational signs and the methodological issues involved in assessing theories about areas beyond immediate empirical access are given consideration.