Your Apple ID is a unique name that identifies you when you operate on iTunes, particularly when you makes purchases in the iTunes Store. iTunes attaches your billing address and payment information with your Apple ID, expediting the purchase process. If you want to change the information saved to your iTunes Store account, including your Apple ID or address, the process takes just moments.
Open iTunes on your computer. Select "iTunes Store" from the sidebar, located on the left side of the screen.
Click "Sign In" in the upper-right corner of the screen. Enter your Apple ID and password. If you are already signed in, your Apple ID will appear in the top corner.
Click "Store" in the toolbar that runs horizontally across the top of the screen. Select "View My Account" from the drop-down menu. Enter your password again and click the "View Account" button. Wait for the Account Information page to open.
Select the "Edit" button to the right of the line that you want to change. You may edit your Apple ID, address, payment information or nickname. After clicking "Edit," a new screen will appear containing your current information. Highlight the information to be changed, delete it and enter the new information. Click "Done" when you are finished.
Click "Done" at the bottom of the Account Information page when you have made the necessary changes to all sections.