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Physical processes governing the formation-evolution of high-redshift galaxies in the epoch of reionization (EoR z>6) are still not well understood. In most cases comma EoR galaxies are fuzzy faint blobs showing little internal structure comma and fitting various theoretical models to spatially-integrated spectral energy distributions (SEDs) is often all that can be done. There are comma however comma a small number of luminous EoR galaxies comma such as Himiko at z=6.595 and CR7 at z=6.601 comma whose exceptional brightnesses have allowed spatially-resolved studies and have revealed some fascinating details. Although such luminous EoR galaxies are rare comma the Subary-Hyper Suprime-Cam (HSC) survey has recently discovered 7 comparably bright EoR galaxies with y < 25 mag (in comparison comma y=25.4 and 24.5 mag with Himiko and CR7 comma respectively). Here comma we propose to obtain HST-WFC3 near-infrared images for these exceptionally luminous z>6 galaxies with the F105W comma F125W comma and F160W filters. Our goals are comma (1) to identify the rest-frame UV continuum morphology comma (2) to measure UV continuum spectral slopes comma and (3) to compare the UV continuum morphology with those of Ly-alpha comma CORCHETE_OPENC IICORCHETE_CLOSE comma and dust emission when possible. The obtained HST data will allow us to probe the internal structures and underlying physical processes in these remarkable high-redshift galaxies. The targeted z>6 EoR galaxies are so bright that they will also make excellent targets for NIRSpec IFU observations comma enabling us to study the internal structure and kinematics of these high-redshift galaxies in greater detail. The obtained HST data will also be essential to make effective us of precious JWST time.