How to add a custom text for order confirmation email template woocommerce

You can add custom text or html using this action.

add_action( 'woocommerce_email_after_order_table', 'add_order_email_instructions', 10, 2 );

  function add_order_email_instructions( $order, $sent_to_admin ) {
   if ( ! $sent_to_admin ) {
     echo 'Custom HTml OR Custom Text';
    }
}