@pinalshah Thank you for your response. I recently found a method to add sku to quote Email. Add below code to foreach loop and <tr> tag, it works well.
// add sku to foreach loop
$product_id = $items->get_product_id();
$_product = wc_get_product( $product_id );
$sku = $_product->get_sku();
// add sku end
<!– add sku to <tr> tag –>
<td style=”text-align:left; border: 1px solid #eee;”><?php echo wp_kses_post( $sku ); ?></td>
<!– add sku end –>
Thanks,
Johnson
