How to change the date and time in iphone?

To change the date and time is very easy in iphone,you click at the ikon settings and the you go to general ,then you scroll down to change date and time.There you will have the options for 24 or 12 hours format ,and then you can choose the city you are or you can just simply click to set it automatically and it will set itself according to the country you choose in the international tab.