Audio is recorded at 24-bit typically. We're not sure what you're asking as the title says 192 (sample rate? different thing), but your text asks how to change a 24-bit file (not song, audio files we assume?) to 32-bit.
If you want all 32-bit float audio files, select them all on the timeline and hit Ctrl+B to bounce them to new files and those new files will be 32-bit float.