Code-Snippets-Functions/Execute a function on a child site/WooCommerce/change-free-download-filename.txt

add_filter('woocommerce_file_download_filename', 'custom_download_filename', 
10, 2);

function custom_download_filename($filename, $product_id) {
// You can replace "free download" with any text you want.
return 'free download';
}