Traveling to US - Do I need to step up / down for Macbook Pro (2016) I live in the U.K. and I have a Macbook Pro (2016) which I purchased in Dubai. The power adapter works fine in U.K. / Dubai / India. 

I am traveling to USA next week. 

Do I need to buy the adapter so that it can be used in the 2-pin USA wall sockets or do I also need to buy something in addition to that - say, a step up / step power adapter (My apologies, I am not sure of what it is called exactly... to transform the voltage as well?)
You only need the correct adapter for your power adapter as it will automatically handle the input voltage

Apple has a World Travel Adapter Kit that supplies adapters for different countries/regions.  What you will need is the the US/Japan adapter included in the kit that has "flat parallel blades with holes."