Save the offer to your eligible card and spend $100 or more, in one or more transactions, in-app or online at THE ICONIC by 15/10/2020 to receive one $15 credit. Limited to the first 20,000 cards to save the offer.
- Excludes gift card purchases.
- Credit should appear on your billing statement within 5 business days from qualifying spend but may take up to 90 days from the offer end date.
I had a look here: https://www.americanexpress.com/au/network/shopping.html and there isn't a manual enrollment link yet.