Seems like a targeted deal as I couldn't find details about this on the ING website.
Apply for an Orange One Low Rate credit card by logging into ing.com.au or using the ING app.
Once approved, make 5 eligible purchases with your new Orange One Low Rate card by 30 June 2021.
To qualify for the bonus offer you must apply and be approved for a new Orange One Low Rate credit card and make 5 eligible purchases before 30 June 2021. Eligible purchases does not include cash transactions (including cash withdrawals from an ATM or over the counter at a bank or cash provider, pseudo cash transactions e.g. gambling, mobile phone top ups and foreign currency and travellers cheques), any purchases refunded, interest, default charges, insurance premiums and other fees and charges debited to your Orange One Account, and any BPay transactions or transactions made which result in spending that exceeds the credit limit it any one month. The $100 bonus will be paid as a rebate into your Orange Everyday account within 60 days of meeting the spend criteria. Existing ING customers who currently hold an Orange One credit card are not eligible for this offer.
$0 Annual Fee