In what situations would it be advisable to use internal links versus external links when integrating content into a PHP website?

When integrating content into a PHP website, it is advisable to use internal links when linking to pages within the same website. This helps improve website navigation and keeps users engaged within the site. On the other hand, external links should be used when linking to external websites or resources that are not part of the website itself.

// Internal link example
echo '<a href="about.php">About Us</a>';

// External link example
echo '<a href="https://www.externalwebsite.com">External Website</a>';