I have devloped a plethora of Apple IDs and Passwords with iCloud, Apple Store, iTunes, Apple Support, etc., etc. and on iPad, iPhone, and MacBook. Where and how do I start to establish a single Apple ID and a single Password which will work with all the devices and applications?
Can't help with iOS devices, since I don't own any and have only one AppleID. Call AppleCare and let them work it out for you. FWIW, the AppleID system is a bit bolloxed, since one can't eliminate or transfer them around. Good luck.
I've done this, but it has not translated to my iPad (which is using an old ID which I can't seem to change).
https://appleid.apple.com/cgi-bin/WebObjects/MyAppleId.woa/ and click the manage button.
Common Apple ID and Password for All Devices and Applications
