files not being posted into $_FILES super global array - php

Question

I am having trouble with a file upload portion of a project. I have created the form with the inputs but when i try to "upload" the file it does not get posted into the $_FILES array. Code posted below. I have declared an enctype within the from tag but the file still does not get posted into the array it only shows Array()
here is my form code:
<?php
require("includes/application_top.php");
$pageTitle = "Add A Product";
require("includes/header.php");
print_r($_FILES);
?>
<div class="container-fluid py-4">
<div class="row ">
<div class="col">
<form method="POST" action="s.php" enctype="multipart/form-data">
<!-- Product Name input -->
<div class="form-outline">
<input type="text" id="ProductName" class="form-control" />
<label class="form-label" for="ProductName"> Product Name</label>
</div>
</div>
<div class="col">
<!-- Product Description input -->
<div class="form-outline">
<input type="text" id="ProductDesc" class="form-control" />
<label class="form-label" for="ProductDesc">Product Description</label>
</div>
</div>
</div>
<hr />
<div class="row">
<div class="col">
<!-- Product Price input -->
<div class="form-outline">
<input type="number" min="0.00" max="10000.00" step="0.01" id="ProductPrice" class="form-control" />
<label class="form-label" for="ProductPrice">Product Price </label>
</div>
</div>
<div class="col">
<!-- Img Upload input -->
<div class="form-outline input-group mb-3 ">
<input type="file" id="ImageUpload" class="form-control" />
<input type="submit" value="Upload" />
</div>
</div>
</div>
</form>
</div>
<?php
require("includes/footer.php")
?>

Answer 1

Any form field must have a name attribute in order to populate PHP's $_GET , $_POST or $_FILES superglobals after submitting the form.
$_GET and $_POST depend on the form method, and $_FILES is specific to file uploads (HTTP POST method only).
Your file input should then look like this:
<input type="file" id="ImageUpload" class="form-control" name="image_upload" />
Given the image_upload name I wrote, you should be able to get the file informations using $_FILES['image_upload].
Read about file uploads in the documentation: Handling file uploads.

Answer 2

You have to provide a name attribute to your fields, both $_POST and $_FILES work on the name attribute, not the ID. id is mostly used when you do something with the field using javascript, like when submitting the form with an ajax request.
In your case, you would need names:
<input type="file" id="ImageUpload" class="form-control" />
would become
<input type="file" name="ImageUpload" class="form-control" />
The same goes for your other input fields, you need a name attribute before you will see then in $_POST.