I was there last year. There are two ways to do this. The first is as mentioned above is an adapter kit that just something to plug into so that it will fit the different outlets. The do not lower the voltage of the outlet so anything you plug into them you may notice them getting hot. These work and it's what I used without any problem but it does happen and is usually more of s problem with things that draw a lot of current like a hair dryer (a lot of these items and other have a switch to go between 110 and 220.
The second option is a converter that will convert the power down from 220 to closer to 110. Sometime these don't always work well. But you will better protect the items you are plugging in.
The down side of a converter is they are expensive and heavier that the adapter kits. As I said I used the kits mainly I was packing light as possible as I did two weeks in Europe with just carry on bags.
Another option if you just want to charge your phone is try is find an Apple Store where your at it for that matter any electronics store and just buy a USB charger for that country then plug your cord in and go. An Apple Store would have the charger for the iPhone designed for that country, but may not be as easy to get too.
I did get from a travel store a small power strip with some surge protection. My daughter use that and the adapter for all her stuff for the six weeks she was there with no problems.