Why iCloud Mail app needs Apple ID to create new iCloud email?

Question

I want to create an iCloud email but Icloud Mail always asks for Apple ID to enter, is this just to open and access app?

Answer 1

Mail thinks you are trying to add a new iCloud account with its own email address.
If you want an additional @icloud.com address you can do one of two things:
1. You can create a new iCloud account by signing out of your existing one in System Preferences>iCloud and signing in with a different Apple ID (if you don't have another one you will have to create it at http://appleid.apple.com ). You can then sign out of it, sign back into the original account, and then add the new account at System Preferences>Mail, Contact and Calendars. This will set your Mail application up with the new address. You won't get 'push' email with this account, it will check the server periodically.
2. The simpler solution is to create an email 'alias' on your existing account. You can have up to three: these are additional addresses (not accounts) and they deliver into the same inbox as the main address. You don't need to do anything in Mail to receive messages to these addresses; if you want to send as from them you can add them in Mail Preferences>Accounts in the 'Email address' field, separating them by a comma. More detail here:
http://help.apple.com/icloud/#/mm6b1a490a
Note regarding option 1 that any one Mac or iOS device can create only three iCloud accounts; this is tied to the hardware, not the user account.