The Avada Woo Checkout Payment Element is helpful when building a one-page checkout. It is the last thing logically in the flow of the checkout, as it is from a button in this Element that users place the order.
So to use this Element, add it to your Checkout layout at the bottom of the design. The Element will pull the payment methods set up in WooCommerce > Settings > Payments. If you use the Checkout Tabs Element, this Element is unnecessary, as all of the other four Checkout Elements are integrated into that one.