If you only have the one volume and don’t expect to use it frequently, then BEBF738VD’s solution will work.
If you are thinking there are multiple qubes that should have access to files in the veracrypt volume, you’ve got a couple of options. The first is to create a dedicated qube for accessing the files on the volume (install veracrypt in that qube’s template, connect the usb volume to it, decrypt there, then qvm-copy the files where they should go). Basically what BEBF738VD said, just using the veracrypt-capable VM as an intermediary.
If for some reason you want direct access from your apps to the qube, then you can install veracrypt on those templates (which means you’ll possibly install it on multiple templates). Or there is a much more complex solution which might make sense if veracrypt is a major part of your life: Split veracrypt - General Discussion - Qubes OS Forum (qubes-os.org) but even as the guy who came up with that, I strongly recommend you do NOT do this unless you find yourself using veracrypt a lot. (It’s a huge part of my qubes infrastructure.)
tl;dr BEBF738VD’s solution is the best unless you use veracrypt a lot.