The Volt is a unit of electric potential. The SI unit of current is the Ampere. You can have very large potential differences (in V) with very small current (in A). The unit of power is the Watt, and 1 W = 1 A*1 V.
So, a given power can be obtained using any voltage, with the proper current. In practice, high currents are unsafe so we tend to avoid that in unprotected sockets. Different norms correspond to different tradeoffs.
The voltage and current combined is the actually important number which is the total wattage available on that circuit. The US standard 220/240V outlet will provide ~30A of current usually while a UK outlet usually has a 13A fuse in the plug matching the circuit's rough availability.
So, a given power can be obtained using any voltage, with the proper current. In practice, high currents are unsafe so we tend to avoid that in unprotected sockets. Different norms correspond to different tradeoffs.