The address you rent, never own
Structurally, a domain reads right to left: the top-level domain (.com, .de, .io), the name registered under it, and any subdomains its owner invents freely (shop.example.com costs nothing — it is just a DNS record). Registration goes through accredited registrars into the TLD's registry, renews annually, and lapses if forgotten — expired domains of active projects are bought by squatters within hours, which makes auto-renewal and a current payment method genuine infrastructure.
The commercially important separation: the domain is not the hosting. Registrars sell hosting and hosts sell domains, but the products are independent — the domain anchors your identity (website, email, every printed card), while hosting is swappable behind it. Keeping the domain in an account you control, rather than registered by an agency or bundled invisibly into a hosting plan, is the difference between changing providers freely and negotiating for your own name. Transfers between registrars are a standardized, code-protected process — mildly bureaucratic, entirely routine.
The domain account is the master key
Whoever controls the registrar account controls where the domain points — website, email, everything. Losing that access (or never having it, because a third party registered 'for' you) is one of the most expensive small mistakes in digital business. Own the account, secure it with 2FA, keep the renewal paid.