How to find out where the website domain is registered?

Domain name registrar is a company that provides services of registration, transfer and administration of your website domain. All information about the domain is stored on the DNS servers of the registrar. 

To find out where the domain was purchased or who is the registrar, it is possible on the WHOIS page of the domain checker service.

In particular, you will get the following data: 

registrar - unique nickname of the registrar
organization - name of the registrar's registered legal entity
Technical Contacts: - list of e-mail addresses, phone numbers, website addresses, registrar.

Whois service allows you to get the full information about the company-registrar of the domain.