In a recursive query, you ask a resolver to do all the work. You send one query and get a final answer. Your home router uses recursive queries to your ISP's DNS server.
In an iterative query, the server returns the best answer it has, which might be a referral. "I don't know, but ask this server." The querying system follows the referrals itself.
Your computer makes recursive queries to a resolver. That resolver makes iterative queries through the DNS hierarchy.