In the Domain contacts option you can manage the default contacts for your domains. This way, you will have the predefined contact when registering a new domain.
To access this section, click on "User management" and then on "Domain contacts" in the top right corner of your Control Panel:
Once you access it, you have the option to "Add contact" to add the registration contact details:
Finally, a form will open and you must complete it with your registration details:
Once the form is completed, click on Save data.