You can change your email at https://account.mojang.com/me/settings. You must have migrated to a Mojang account in order to do this. You can migrate an account at https://account.mojang.com/migrate.
If you have not migrated your account, you have a typo in your email, or if for some reason you do not have access to your original account, please locate the transaction ID or gift code from when the account was purchased so we can verify account ownership, and click HERE.
