Studying the host galaxies of high-redshift quasars provides vital insights into the early growth of supermassive black holes and the black hole—galaxy connection. JWST has launched a new era in this field, providing the opportunity to observe the stellar components of these host galaxies for the first time, due to its exquisite spatial resolution and infrared spectral capabilities. I will present our latest results from a range of JWST programs aiming to measure high-z quasars and their host galaxies, including two z=6.8 quasars from the Galaxy Assembly with NIRSpec IFS GTO program. We have measured their black hole properties and a wide range of host properties, for example their interstellar medium structure and kinematics, star formation rates, and outflows, as well as discovering that both have merging companion galaxies. I will summarize our latest results and outline the plans for the rest of our upcoming observations studying quasars and their host galaxies with JWST.