Crash a moon into it
If your civilisation has advanced to the point where they are terraforming planets thanthen you can do some pretty big things.
If you just want to get a lot of water onto Mars and don't mind destroying everything on the surface in the process, how about one of thethere are several moons of Jupiter into it?
Ganymede and Europa each have more water than Earth does. Ganymede is ~25%other bodies in the mass of Mars. Europa is less apocalyptic at only ~7%. So there'd be some pretty big fireworks when they collide but Mars should survive and oncesolar system with enough water to cover the dust settlesplanet in a few years there'll be plenty of waterone go.
If that'sHere's a bit too much then there's always something like Enceladus. It only has ~1%helpful chart of the largest bodies of water that earthin the solar system (based on current estimates). Mars has but mars is smaller anywaya volume of ~163 ZL so maybe that's enoughthe top 3 would be closer to getcrashing Mars into another Mars. But hey if we're gonna be terraforming anyway maybe you startedwant to make it a bit bigger.
