If the domain owner has hidden their information, it can be difficult to contact them. However, there are a few things you can try:
Contact the domain registrar: The domain registrar is the company that registered the domain name. They will have the contact information for the domain owner, even if it is hidden.
Use a WHOIS lookup: A WHOIS lookup is a service that can be used to find information about a domain name, including the domain owner's contact information. However, if the domain owner has hidden their information, this may not be successful.
Send a message to the domain's email address: If the domain owner has provided an email address for the domain, you can try sending them a message. However, there is no guarantee that they will read or respond to your message.
Hire a lawyer: If you need to contact the domain owner for legal reasons, you may need to hire a lawyer. A lawyer can help you to send a formal demand letter to the domain owner and to take other legal action if necessary.