Hooking into the native WooCommerce product import

functions.php

<?php
  
  //Since 3.x WooCommerce has had an excellent native product import/export.
  //You can do a huge amount just by tweaking your CSV to load meta values into the correct meta fields for your destination site.
  //It'll even import images from the source site by URL if possible, and upload them to the destination site.
  
  //If you need to do something a little fancier for every product you import, check out the woocommerce_product_import_* hooks here https://woocommerce.github.io/code-reference/hooks/hooks.html 
  //You can modify the CSV data before it's used, and modify the resulting WC_Product during and after creation
  
  //eg do something to every product after it's created
  function mytheme_add_product_content($product, $data){
    //$product is a WC_Product
    //$data is an array of data pulled from the CSV


  }//mytheme_add_product_content()
  add_action('woocommerce_product_import_inserted_product_object', 'mytheme_add_product_content',10,2);