iCloud: iCloud account
The Apple ID email address and password you use to turn on and use iCloud features and to access the web applications at icloud.com.
You can use the same Apple ID that you use with iCloud to access many Apple services, such as the Apple Online Store, the iTunes Store, the App Store, and the Mac App Store. When you’re asked to sign in using your Apple ID, enter the same email address and password you used to turn on iCloud.
You can find your iCloud account information in these places:
On your iOS device, tap Settings > iCloud.
On your Mac, choose Apple Menu > System Preferences, then click iCloud.
On a Windows computer, if you have Windows 8, move the pointer to the upper-right corner of the screen to show the Charms bar, click the Search charm, and then click iCloud Control Panel on the left. If you have Windows 7 or Windows Vista, choose Start menu > All Programs > iCloud > iCloud.