How can restructuring the index.php file and separating HTML content from PHP logic help resolve header-related issues in PHP?

Restructuring the index.php file and separating HTML content from PHP logic can help resolve header-related issues in PHP by ensuring that header functions like `header()` are called before any output is sent to the browser. This separation allows for better control over when headers are set, preventing conflicts that can arise when headers are set after content has already been sent.

<?php
// Set any headers before any output is sent
header('Content-Type: text/html');

// Separate HTML content from PHP logic
?>
<!DOCTYPE html>
<html>
<head>
    <title>Header Issue Resolution</title>
</head>
<body>
    <h1>Header Issue Resolved!</h1>
</body>
</html>