Your pay.com.au account allows you to re-imburse your credit card and earn PayRewards while doing so.
As this type of transfer can only be done when funded by a bank account, you will first need to add your nominated bank account as a payment method within your PayWallet.
View below article on how to manage payment methods:
Once you have added your bank account in your PayWallet, you will need to create your credit card as a payee, within the Payees tab. Your credit card's payment instructions are provided on your credit card statement.
View below article on how to manage payees:
You will now be able to make your payment via the Make a payment > Supplier Payment workflow.