Most American appliances run on 120 volt power. Some larger appliances such as washers and dryers, however, run on 220 or 240 volt power. This is because these appliances require more energy.
Most 120 volt outlets have two long thin holes lined up parallel with each other and they sometimes have a third circular hole beneath them. These are, by far, the most common outlets in America. Several different types of 240 volt outlets exist, but the majority of these are in a large circular casing. The holes in a 240 volt outlet all tend to be rounded or oddly shaped.
Countries like America and Canada use 120 volt power, but most of the rest of the world runs on 220 to 240 volt power. Step-up or step-down transformers can be bought that change 120 volt power into 240 volt power and vice versa.
