If you have the steam version:
copy your game folder somewhere out of the steam folder. then un-install the game in steam.
add the location you plan to move the game to as a new steam library location in the steam settings, then copy the entire game folder you backed up to that location. (make sure to emulate the folder structure of the original steam library, eg. (your new location)/Steam/steamapps/common/Zenimax Online)
After you've done that, go into steam and "re-install" the game, make sure to choose the new library location you moved the game to and when steam starts that stage where it'll allocate disk space, it should after a moment change to say "discovered existing game files" or something similar.
The game will then install, but without having to download it again, so it'll still take a little time, but much, much, much faster than straight up re-downloading it.