The answer
Transfer ordering is currently still in preparation. An existing domain cannot be taken over through a normal new-registration order. Contact us if you are planning a transfer so we can check current options.
A domain transfer does not automatically move website files or mailboxes. Keep existing services available until the change has been planned and checked.
What to do
Note the domain, its current status and the ongoing services you need.
Save existing DNS records and do not cancel services prematurely.
Ask support about current transfer options; do not send access codes unsolicited.