Windows builds are for 32 and 64 bit systems.
The links for Windows packages on https://www.torproject.org/projects/torbrowser.html only say 32-bit. Users are emailing the help desk asking where the 64-bit packages are. But it's the same package. The web page should be clearer.
I think the links should say '32/64-bit' where they now say '32-bit'.