Is the Ipad dual voltage?

Voltage is not an issue. However, there is a good probability that you will need a mechanical adapter so that the plug fits properly into the receptacle.

The iPad charger is rated 100-240 volts at 50-60 Hertz so will work in most systems. The plug pin configuration may need to be adapted to the country or countries you visit. Apple sells a World Travel kit of pin blocks for the charger that will fit most countries. The pin block on the charger slides off horizontally and the proper pin set then slides on.

Or, many international airports carry adapters that you can plug the charger into then plug into the outlet.