Sir I have following codes

PHP Code:
<?php
if(isset($_POST['button1'])) {
    
$aa $_POST['text1'];
        echo (
"My name is " $aa);        
}
?>

<html>
<head>
<title>First form</title>
</head>    
<body>

<form name="aa" action="mix.php" method="POST">
    Name<input type="text" name="text1" value="">
    <input  type="submit" value="display" name="button1">
</form>
        
</body>    
</html>
These codes have no error message.
I am beginner so I request you to please check whether I am doing right.

Second Request:

Is it possible to use php codes in <html> tag.
if yes then please adjust my php code in html tag.

Thanks in advance