PHP script starts with <?php and ends with ?>, between PHP code is used to add program logic.
<?php or <?PHP both are allowed.
PHP scripts can be placed anywhere in php file. PHP every statement ends with semicolon ;
Example
<!DOCTYPE html>
<html>
<body>
<h1>My first PHP page</h1>
<?php
echo "Hello World!";
?>
</body>
</html>PHP Case Sensitivity
PHP is a not fully case sensitive language, it means PHP only treats variable name as case sensitive, while function, class, construct are not case sensitive.