Buying a mac pro (2013) overseas
As far as I'm aware, all Macs are multi-voltage...
All you'd need to change is the plug at the wall end [or swap for another IEC cable]

From Apple - Mac Pro Specs


Line voltage: 100-240V AC
Frequency: 50Hz to 60Hz, single phase


It takes a standard IEC to a local mains plug. ['kettle plug' they're sometimes called, though technically inaccurately as a kettle plug has a notch out of it]