Core-collapse supernovae (CCSNe) are the explosive endpoints of massive stars and play an important role in stellar evolution. Among them, hydrogen-rich Type II SNe are characterized by the presence of hydrogen in their spectra, indicating that their progenitors retain a significant hydrogen envelope prior to explosion. By studying them, the progenitor system, surrounding circumsteller medium (CSM) and the the physical processes governing stellar explosions can be explored. This thesis presents a comprehensive photometric and spectroscopic investigation of three Type IIP SNe 2018pq, 2022xus, and 2023zcu—using observations obtained from Indian and international facilities. Detailed light curve and spectral analyses, combined with analytical, radiative-transfer, and hydrodynamical modeling, constrain several important properties, including the progenitor radius, initial mass, explosion energy, synthesized nickel mass, and the CSM characteristics. While the three SNe originate from progenitors with comparable masses, they exhibit diverse observational properties, demonstrating the influence of hydrogen-envelope mass and early time CSM interaction with the SN ejecta. The thesis also examines the long-standing Type IIP/IIL conundrum through a detailed analysis of SN 2022xus, providing strong observational evidence that these subclasses form a continuum rather than two distinct populations. A systematic sample study on the long-plateau Type IIP SNe further investigates the origin of their unusually extended photospheric phase and shows that progenitor mass is one of the primary factor controlling plateau duration, while most events are associated with relatively low to normal explosion energies. Finally, observations from the 4 m International Liquid Mirror Telescope (ILMT) demonstrate the growing importance of high-cadence survey telescopes in transient astronomy by enabling the discovery, monitoring, and photometric characterization of SNe. Overall, this work highlights the crucial role of early-time observations, multi-wavelength monitoring, and modern modeling techniques in advancing our understanding of the progenitors, explosion mechanisms, and diversity within Type II SNe.