How can PHP variables be properly integrated into HTML code for output?

To integrate PHP variables into HTML code for output, you can simply echo the variable within the HTML code using the PHP echo statement. This allows you to dynamically display the value of the variable within the HTML content.

<?php
$variable = "Hello, World!";
?>

<!DOCTYPE html>
<html>
<head>
    <title>PHP Variable Integration</title>
</head>
<body>
    <h1><?php echo $variable; ?></h1>
</body>
</html>