WhoIs is a database of domain registrants so you can see who is behind a domain and get in contact with them. Registrants can choose to hide most of their information so it remains private, though a registrar such as GoDaddy is able to get in contact with the owners of domains that were registered via their own domain registrar companies.
The official WhoIs website is found at the URL https://whois.icann.org/en; however, sometimes it isn’t as reliable for retrieving information compared to third-party WhoIs sites such as https://who.is/.
WhoIs is not an acronym but rather short for the phrase who is behind this domain? While the idea behind WhoIs is useful, often a domain registrant is protected and limited information is available in the WhoIs database. That said, you usually can see enough to let you know if a registrant is in the same location, though just because a registrant says they are from a particular location when they register a domain name doesn’t guarantee that they are from that location. Domain registrars such as GoDaddy prompt registrants letting them know that lying about a registrant’s location is illegal. GoDaddy also sends emails to registrants yearly and asks registrants to check the addresses given to ensure they are kept up to date. In general, most registrants don’t want to lie because the penalty involved in getting caught lying about an address isn’t worth the risk. Registrants caught lying about their locations are subject to fines or losing the license to the domain names associated with the false information.