WooCommerce – Print Processing orders [closed]

Here’s the solution:

  1. Remove the SKU table header
  2. Add (SKU) to the Product header Product (SKU)
  3. pass false, true in email_order_items_table function $order->email_order_items_table(false, true)

This is not the visual result you were expecting, but it works and it shows the SKU. The second parameter in email_order_items_table indicates whether to show the SKU or not.