WooCommerce Send Order Invoice Upon Placing Order

/*
 * Automatically send order invoice to customer, once order is placed.
 *
 * Works only when order status is "pending".
 */
function dctit_custom_woocommerce_pending_order_invoice_notification( $order_id ) {
    $order = wc_get_order( $order_id );

    //should not be doing anything, if order is not in pending status
    if( ! $order->has_status( 'pending' ) ) {
        return;
    }

    //send email
    WC()->mailer()->get_emails()['WC_Email_Customer_Invoice']->trigger( $order_id );
}
add_action( 'woocommerce_checkout_order_processed', 'dctit_custom_woocommerce_pending_order_invoice_notification', 20, 1 );