If your Shopify store sells gift cards, you may want to treat those sales in a special way - for example you may wish to record them as a credit in a liability account, rather than as a sale.
In A2X you can do this using Product Types. Product Types allow you to group sales of certain products together, and then apply different accounting and tax treatment to them on the Accounts and Taxes screen.
First you need to know what SKU or SKUs you use for your Gift Card products, let's suppose you sell 3 gift cards with these SKUS: GIFT50, GIFT100 and GIFT200 - for $50, $100 and $200 gift cards.
Then you create your new product type in Settings > Product Types, like this:
Once created, you'll tell A2X to use these for sales group on the Settings > Invoices tab:
Lastly, refresh a few payouts to see the settings take effect, you should see a separate transaction line in your payout, and you can now apply accounts and taxes to these in the Account and taxes page.
When gift cards are used, you will see sales applied to the Gateway gift_card account - this can then be your gift card liability account, to reflect the reduced liability as the cards are used.