Freenom free domains only grant you usage rights. The registrant listed in WHOIS is still their company. You don't own the domain. I have a few Freenom domains

Freenom free domains only grant you usage rights. The registrant listed in WHOIS is still their company. You don't own the domain. I have a few Freenom domains, but they are only for short-term use (e.g. try out a new ACME client). Nobody should use a Freenom domain on a serious website.