yeah as I mentioned in FAQ section, there is no email hook till current woocommerce version but the woo developers has added the email hook in woocommerce version 3.1,
so for now you have to edit the core woocommerce file if you want email functionality working.
find these lines in woocommerce/woocommerce.php
// Email Actions
$email_actions = array(
'woocommerce_low_stock',
'woocommerce_no_stock',
'woocommerce_product_on_backorder',
'woocommerce_order_status_pending_to_processing',
'woocommerce_order_status_pending_to_completed',
'woocommerce_order_status_pending_to_on-hold',
'woocommerce_order_status_failed_to_processing',
'woocommerce_order_status_failed_to_completed',
'woocommerce_order_status_completed',
'woocommerce_new_customer_note',
'woocommerce_created_customer'
);
replace above lines with
// Email Actions
$email_actions = apply_filters( 'woocommerce_email_actions', array(
'woocommerce_low_stock',
'woocommerce_no_stock',
'woocommerce_product_on_backorder',
'woocommerce_order_status_pending_to_processing',
'woocommerce_order_status_pending_to_completed',
'woocommerce_order_status_pending_to_cancelled',
'woocommerce_order_status_pending_to_on-hold',
'woocommerce_order_status_failed_to_processing',
'woocommerce_order_status_failed_to_completed',
'woocommerce_order_status_on-hold_to_processing',
'woocommerce_order_status_on-hold_to_cancelled',
'woocommerce_order_status_completed',
'woocommerce_new_customer_note',
'woocommerce_created_customer'
) );
Thanks