How can PHP users ensure that their code is properly indexed or cached by search engines like Google?

To ensure that PHP code is properly indexed or cached by search engines like Google, users can utilize meta tags in their HTML output. By including meta tags such as "robots" for indexing instructions and "cache-control" for caching directives, users can provide search engines with the necessary information to properly index and cache their content.

<?php
header('Cache-Control: public, max-age=3600'); // Cache content for 1 hour
echo '<meta name="robots" content="index, follow">'; // Instruct search engines to index content
?>