SellerZen will process orders with international sales tax into QuickBooks Online using a service item since QuickBooks Online doesn't support international sales tax.
To process sales tax for international marketplaces like Amazon Canada, you'll have to create a service item that is linked to a sales tax payable liability account.
Make sure that the "Is taxable" box is unchecked for the service item and that the currency on the sales tax payable account is correct.
We recommend that you track sales tax for each province or region in separate service items and accounts. You can always use sub-accounts to group them. This allows for better reporting.
Once you create the service items, you can map them on the Taxes tab under the marketplace settings on SellerZen.
Once orders are processed, the account(s) will reflect sales tax from your international sales.