Electrons in quantum materials interact via the Coulomb interaction, giving rise to a rich variety of collective phenomena, including magnetic excitations, charge-density fluctuations, and superconductivity. A major challenge in theoretical condensed matter physics is to describe these effects quantitatively. One widely used approach is the GW approximation, which describes electronic properties in terms of the interaction between electrons and dynamically screened Coulomb fluctuations. However, in materials where magnetic correlations play a dominant role, an accurate treatment of spin fluctuations is particularly important. Developing computationally efficient methods that capture these effects while remaining applicable to realistic materials is an important challenge. The goal of this internship is to implement and develop a magnetic GW approach that incorporates the effects of magnetic fluctuations into the description of correlated electrons, and to apply this method to realistic quantum materials. The project combines theoretical method development, numerical implementation, and the investigation of physical phenomena. It offers an opportunity not only to develop a computational tool but also to apply it to fundamental questions concerning the interplay between electronic quasiparticles and collective magnetic excitations in realistic quantum materials.