Moving Files to Another Drive

SpookeyKitty_4  Do you want to install Sims 4 on the other drive, or move your user data, or both?  The game itself can be installed without your doing anything special—simply uninstall it through the EA App and reinstall in the new location of your choice.

If you want your saves, mods and cc, and other user data on the secondary drive, you'll need to create a symbolic link to tell the game where to look.  Here's how:

https://crinrict.com/blog/2020/02/moving-windows-documents-folder-to-external-drive-via-symbolic-link.html

If you're going to do both, it would be best to create folders on the secondary drive, one for each type of data.  So you might install the game to D:\Games and move the user folder to D:\Sims Data, or really whatever you want as long as they're not in the same location.