Iowa Code § 420.237: Certificate of purchase.

The treasurer or collector of taxes, or person authorized to act as collector, shall make, sign, and deliver to the purchaser of any real property sold for the payment of any taxes or special assessments authorized by the provisions of this chapter, or by any law applicable to such cities, a certificate of purchase, which shall have the same force and effect as certificates issued by county treasurers for the sale of property for delinquent county taxes.