Apple email change.

iCloud: Create an iCloud Mail email address

If you set up iCloud using an Apple ID that doesn’t end with @icloud.com, you must create an @icloud.com email address on your iOS device or Mac before you can use iCloud Mail.

Note: If you set up iCloud using an Apple ID that ends with @mac.com or @me.com, you don’t need to set up an @icloud.com email address to use iCloud Mail. You already have an equivalent address that ends with @icloud.com.

• On your iOS device (iOS 10.3 or later): Go to Settings > [your name] > iCloud, turn on Mail, then follow the onscreen instructions.
• On your iOS device (iOS 10.2 or earlier): Go to Settings > iCloud, turn on Mail, then follow the onscreen instructions.
• On your Mac: Choose Apple menu  > System Preferences, click iCloud, select Mail, then follow the onscreen instructions.

If you don’t see onscreen instructions after turning on iCloud Mail on your iOS device or Mac, you already have a primary iCloud Mail email address. To create an email alias, see Use email aliases in Mail on iCloud.com.

After you set up your @icloud.com email address, you can use it to sign in to iCloud. You can still sign in using the Apple ID you used when you set up iCloud.

iCloud: Create an iCloud Mail email address - Apple Support

https://support.apple.com/kb/ph2620

Read this support guide:--> Change your Apple ID - Apple Support

Regards

Giulio