How to write html code inside <?php ?>, I want write html code within the PHP script so that it can be echoed from Backend

You can do like

HTML in PHP :

<?php
     echo "<table>";
     echo "<tr>";
     echo "<td>Name</td>";
     echo "<td>".$name."</td>";
     echo "</tr>";
     echo "</table>";
?>

Or You can write like.

PHP in HTML :

<?php /*Do some PHP calculation or something*/ ?>
     <table>
         <tr>
             <td>Name</td>
             <td><?php echo $name;?></td>
         </tr>
     </table>

<?php /*Do some PHP calculation or something*/ ?> Means:
You can open a PHP tag with <?php, now add your PHP code, then close the tag with ?> and then write your html code. When needed to add more PHP, just open another PHP tag with <?php.

You can drop in and out of the PHP context using the <?php and ?> tags. For example...

<?php
$array = array(1, 2, 3, 4);
?>

<table>
<thead><tr><th>Number</th></tr></thead>
<tbody>
<?php foreach ($array as $num) : ?>
<tr><td><?= htmlspecialchars($num) ?></td></tr>
<?php endforeach ?>
</tbody>
</table>

Also see Alternative syntax for control structures

Try it like,

<?php 
    $name='your name';
    echo '<table>
       <tr><th>Name</th></tr>
       <tr><td>'.$name.'</td></tr>
    </table>';
?>

Updated

<?php 
    echo '<table>
       <tr><th>Rst</th><th>Marks</th></tr>
       <tr><td>'.$rst4.'</td><td>'.$marks4.'</td></tr>
    </table>';
?>