if you are having issues with wordpress\woocommerce and paypal, then I recommend using this code, which is copy paste from the woocommerce website. You can visit the original page here at woocommerce.com/document/automatically-complete-orders/
/**
* Auto Complete all WooCommerce orders.
*/
add_action( ‘woocommerce_thankyou’, ‘custom_woocommerce_auto_complete_order’ );
function custom_woocommerce_auto_complete_order( $order_id ) {
if ( ! $order_id ) {
return;
}
$order = wc_get_order( $order_id );
$order->update_status( ‘completed’ );
}
