Why do I keep seeing the undefined index error for line 13 ('file')? - indexing

Question

I am trying to create a simple drag and drop page using php. When I click the "submit" button, I get an error: Notice: Undefined index: file in C:\xampp\htdocs\phpfiles\DragAndDrop\includes\gallery-upload.inc.php on line 13. Why is it not reading the "file" index from the htmlphp?
Here is the HTML and PHP code:
enter code here
<!--continuted from HTML page-->
</section>
<?php
$_SESSION['username'] = "Admin";
if (isset($_SESSION['username'])) {
echo '<div class="gallery-upload">
<form action="includes/gallery-upload.inc.php" method="post" enctype="mutipart/form-data">
<input type="text" name="filename" placeholder="File Name...">
<input type="text" name="filetitle" placeholder="Image Title...">
<input type="text" name="filedesc" placeholder="Image description...">
<input type="file" name="file">
<button type="submit" name="submit">Upload</button>
</form>
</div>';
}
?>
</main>
</body>
</html>
<!--and the php page-->
<?php
if (isset($_POST['submit'])) {//checks submit form and posts the info
$newFileName = $_POST['filename'];
if (empty($_POST['filename'])) { //if filename is emptly
$newFileName = "gallery"; //if filename is empty, generates name
} else {
$newFileName = strtolower(str_replace(" ", "-", $newFileName)); //if spaces are in the name, creates stringholder
}
$imageTitle = $_POST['filetitle'];
$imageDesc = $_POST['filedesc'];
$file = $_FILES['file'];
}
?>

Answer 1

You have a typo:
mutipart/form-data
Should be
multipart/form-data