Check when a domain was registered, when it expires, who the registrar is and which name servers it uses - using the official RDAP service that has replaced WHOIS. It also tells you if a name looks available.
RDAP is the modern replacement for WHOIS. It returns structured data over HTTPS from the official registry of each domain ending, so the dates, status and name servers shown here come straight from the source.
Most registries now hide personal contact details to protect privacy (GDPR). You will see the technical record - registrar, dates, status and name servers - but not the owner's identity.
The "Expires" box shows the date and how many days are left. Renew early: after expiry a domain can stop working and may enter a costly redemption period.
It usually means no one has registered it, so it is likely available. Confirm at a registrar before you rely on it - some names are reserved, premium-priced or restricted.