A domain can be easy to overlook when several suppliers handle your website, email and billing. Keep a short inventory so the person responsible knows where to renew it.
Record the domain, registrar, renewal date and account owner. Verify that the renewal notices go to an inbox the owner can reach. Add reminders far enough ahead to correct an expired payment method or regain access to the account.
For a handover, add the location of the DNS settings and the person who can approve changes. Keep passwords in your usual password manager. Review the inventory when a project changes hands or you move a service.