How to get value of text area using PHP?

This is sub page code of my project here here user can edit text so I have used text-area but the problem here is I don’t know how to get text or value of text-area using PHP so I can update it back to serve?

<?php

$eid = $_GET['id'];

$con = mysqli_connect("localhost","root","","news") or die("Connection Failed!");
$sql = "SELECT * From content where pid = {$eid}";
$result = mysqli_query($con, $sql) or die("Query Failed!");

$t = mysqli_fetch_assoc($result);

?>

<html>
  <head></head>
  <link rel="stylesheet" href="bootstrapcssbootstrap.min.css">
<body>

<div class="container mt-2">
  <h1><?php echo $t['title'] ?></h1>
  <textarea type="text" name="edit-box" id="edit-box" class="w-75 p-3 mt-3 h-75">
      <?php echo $t['article'] ?>
  </textarea>
  <button type="button" name="button" class="btn btn-primary mb-4">Update</button>
</div>


<!-- PHP: Sending updated data to server -->
<?php
  
?>


</body>

</html>