How can direct inclusion of strings in HTML files differ from including them through PHP files in terms of character encoding?

Direct inclusion of strings in HTML files can lead to character encoding issues because HTML files do not have a specified character encoding by default. On the other hand, including strings through PHP files allows for specifying the character encoding using functions like `header()` or `meta` tags, ensuring that the correct encoding is used for displaying the content.

<?php
header('Content-Type: text/html; charset=UTF-8');
echo "<html><head><meta charset='UTF-8'></head><body>";
echo "Your content goes here";
echo "</body></html>";
?>