Prism Windows is a 32-bit application but runs fine on 64-bit Windows. Prism Windows automatically installs an indexing addon that lets you search for Prism files using any term in titles, legends, notes, etc. Prism Mac is a 32-bit application. It will run on either 64- or 32-bit machines. Prism Windows automatically installs an appropriate edition - 64-bit or 32-bit - of an indexing addon that lets you search for Prism files using any term in titles, legends, notes, etc. Prism Windows is a 32-bit application but runs fine on 64-bit Windows. It will present a clear message if you have a mismatch. If you don't know what you have, just try one. Prism Windows comes with two installers, one for 32-bit Windows and one for 64-bit Windows.
Prism Mac is a 64-bit application, as current versions of MacOS are 64 bit.