Does WooCommerce Connect Import Products for adding to Invoices?
No. WooCommerce Connect imports your WooCommerce orders and customers. It doesn’t import your WooCommerce Product list for adding to invoices.
This is because the functionality of WooCommerce means you should let WooCommerce run your eCommerce store.
If you need to create an Invoice for your WooCommerce orders, then you can do this from the WooCommerce order page (and actions). As shown below.
So, if you want to generate invoices for your WooCommerce products then you can do it directly from your WooCommerce stores order page.