Improve multiple line items support in Zapier extension
Right now, you can't get multiple line items from a WooCommerce order into, for instance, a Xero invoice via Zapier.
It seems to be a limitation of the Zapier add-on for WooCommerce because Zapier-Xero integration does have this capability working with other source systems, such as Shopify and Magento.
Patrick Pettibon commented
This would be a nice upgrade. Right now I have to go through the order using my own code to separate out line items. It's a pain, and I suspect that many or most users would not go to the trouble of solving this issue on their own.
Unfortunately this isn't possible to implement until the Zapier Developer platform is improved to support arrays (line items).
Some services (such as Xero/Shopify) are created by Zapier themselves (without using the Zapier Development platform), which is how they are able to implement line item handling.
When Zapier adds line item (array) support to their developer platform, then the WooCommerce Zapier extension will be updated to support it.