Electric voltages across the world differ so you need to know what type of voltage is used in the country you're travelling to, otherwise you may overheat your appliance.
Most electric shavers will adapt to the alternative current voltages - 100-240V - used across the world. For safety always check the voltage requirement for your shaver which should be in your manufacturer's instruction booklet.
If you are able to use your device overseas, remember you will probably have to take a travel adaptor plug which can be bought at electrical and travel stores.
If you travel a lot it may be worth investing in a battery operated travel shaver which usually comes complete with batteries.
Note: If you are travelling light and not taking hold baggage on an aeroplane, electric razors can be carried in your hand luggage.