Domain owners are required keep WHOIS data of their domain names correct and up-to-date at all times under ICANN’s policy.
It includes registrant, administrative, technical, billing, and contact information (contact info is only for .jp).

※ICANN：A non-profit corporation that was formed to assume responsibility for the allocation or management of domain names, IP addresses, protocols, and root servers.

Z.com Domain offers “WHOIS Privacy Protection ” for people would not like their personal information displayed in the public. Please note that we may stop providing WHOIS Privacy Protection service when there happens to be domain name dispute, or causes domain management problems.

You’re required to complete the registration information when you apply for WHOIS Privacy Protection. You can cancel the service after you signed up.
You can also extend, or cancel the service when you renew domain name.