How can multiple HTML and body tags in a PHP document affect the functionality of the code?

Having multiple HTML and body tags in a PHP document can cause issues with the structure of the HTML output and potentially break the layout of the webpage. To solve this issue, you should ensure that there is only one set of HTML and body tags in the PHP document, encapsulating the entire HTML content.

<?php
// Start PHP code
// Other PHP logic here

// Output HTML content
echo "<!DOCTYPE html>";
echo "<html>";
echo "<head>";
echo "<title>My Page</title>";
echo "</head>";
echo "<body>";

// Your HTML content here

echo "</body>";
echo "</html>";
// End PHP code
?>