This page explains how WooCommerce Order Completion works in China Payments Plugin.
WooCommerce Order Completion
By default, WooCommerce will only auto-complete paid orders for products that are both Virtual and Downloadable, assuming that the shop needs to fulfill/ship any orders that don’t meet these criteria.
If your orders are not auto-completing and you want them to do so, then the workaround would be to ensure that your products are marked as both Virtual and Downloadable.
Marking products as both Virtual and Downloadable may enable the Downloads menu item in the WooCommerce Account area accessed by users. This can be hidden with CSS.
Payment Confirmation
We've optimized China Payments Plugin with 3 methods for verifying payment confirmation: