How can variables from a PHP file be inserted into an HTML file?

To insert variables from a PHP file into an HTML file, you can use PHP's echo or print statements within the HTML code. This allows you to dynamically display the variable values within the HTML output. Simply open the PHP file, assign values to variables, and then echo or print those variables within the HTML file where needed.

<?php
$variable1 = "Hello";
$variable2 = "World";
?>

<!DOCTYPE html>
<html>
<head>
    <title>PHP Variables in HTML</title>
</head>
<body>
    <h1><?php echo $variable1; ?>, <?php echo $variable2; ?>!</h1>
</body>
</html>