To up the account on your iPad, go to Settings>iCloud, enter and Apple ID, once verified you can turn Mail to On in Settings>iCloud, which will create the account automatically. (Also, you can't go to icloud.com to view your account on your iPad. This can only be done on your computer. On you Mac, go to System Preferences>iCloud, sign into your iCloud account and turn Mail to On (requires OS X 10.7.4 or higher). To set your default account go to Mail>Preferences>Composing>Send New Messages From, the set as desired.