Grab the SKU by looping through the items

tamara-olson-designs-grab-sku.php

$items = $order->get_items();

// Loop through ordered items
foreach ($items as $item) {
  
  $product_name = $item['name'];
  $product_id = $item['product_id'];
  $product_variation_id = $item['variation_id'];
                  
  // Check if product has variation.
    if ($product_variation_id) { 
      $product = new WC_Product($item['variation_id']);
    } else {
      $product = new WC_Product($item['product_id']);
    }

  // Get SKU
  $sku = $product->get_sku();
                  
  // Echo SKU
  echo "<h2>SKU: ";
  echo $sku;
  echo "</h2>";
} // end foreach