You can change it directly on your end. If you want to change your email address, you should do so via the ingame system. Go to Settings > Account Settings > Change your email. Then, please follow the instructions.
IMPORTANT: to change the email address of your account, you must have access to the existing email address! Otherwise, you will not be able to change your email address. If you no longer have access to your current email address, we invite you to resolve this issue with your email provider.
No, you can not migrate your account from one platform to another.
In order to validate your account, you need to create your account with a valid email address. Otherwise, you won’t be able to contact the Support service.