IP Whois Lookup Tool checks a given IP Address against the IP Address owners database. Every IP Address used on the internet is owned by some organization or individual, and no one else can use the IP Address except the real-owner of an IP Address.
Majorly, the IP Addresses on the internet are owned by organizations or ISPs and those organizations have been assigned a vast number of IPs so that they can assign those IPs to their users or clients on a considerable amount to maintain uniqueness for their users. Some ISPs do not assign the same IP to multiple users, however many ISPs follow the shared IP practice and assign one IP to many users to manage into their quota. The IP Address Ownership tells the name of the original organization or individual whose name the IP is registered in the IP Whois Database, and does not tell the Whois details of the real user to whom the Internet Service Provider assigns the IP.
It is impossible to see the name, address, and contact of the real user who actually is using the IP Address, and only the Whois Details can be seen for the actual owner to whom the IP actually belongs or is registered.