Warning: Undefined array key, Trying to access array offset on value of type null in PHP

Question

I'm not being able to insert any data to MySQL database due to this error that I'm getting after inserting and submitting the form.

Warning: Undefined array key "image" in C:\xampp\htdocs\eCommerce\admin\items.php on line 304

Warning: Trying to access array offset on value of type null in C:\xampp\htdocs\eCommerce\admin\items.php on line 304

Warning: Undefined array key "image" in C:\xampp\htdocs\eCommerce\admin\items.php on line 305

Warning: Trying to access array offset on value of type null in C:\xampp\htdocs\eCommerce\admin\items.php on line 305

this is some code of items.php:

elseif ($action == 'Add') {

        ?>

<h1 class="text-center">Add New Item</h1>
<div class="container">
    <form class="form-horizontal" action="?action=Insert" method="POST" enctype="multipart/form-data">
 <div class="form-group form-group-lg">
        <label for="image" class="col-sm-2 control-label">Item Image</label>
        <div class="col-sm-10 col-md-6">
            <input type="file" name="image" id="image" class="form-control" required="required">

        </div>
    </div>


    <!-- End Tags Field -->
    <!-- Start Submit Field -->
    <div class="form-group form-group-lg">
        <div class="col-sm-offset-2 col-sm-10">
            <input type="submit" value="Add Item" class="btn btn-primary btn-sm" />
        </div>
    </div>
    <!-- End Submit Field -->
    </form>

</div>

<?php

    } elseif ($action == 'Insert') {

        if ($_SERVER['REQUEST_METHOD'] == 'POST') {

            echo "<h1 class='text-center'>Insert Item</h1>";
            echo "<div class='container'>";

            // Get Variables From The Form

            $name = $_POST['name'];
            $desc = $_POST['description'];
            $price = $_POST['price'];
            $country = $_POST['country'];
            $status = $_POST['status'];
            $member = $_POST['member'];
            $cat = $_POST['category'];
            $tags = $_POST['tags'];
line 304:   $image = $_FILES['image']['name'];
line 305:   $tmpImage = $_FILES['image']['tmp_name'];

            // Validate The Form

            $formErrors = array();

            if (empty($name)) {
                $formErrors[] = 'Name Can\'t be <strong>Empty</strong>';
            }

            if (empty($desc)) {
                $formErrors[] = 'Description Can\'t be <strong>Empty</strong>';
            }

            if (empty($price)) {
                $formErrors[] = 'Price Can\'t be <strong>Empty</strong>';
            }

            if (empty($country)) {
                $formErrors[] = 'Country Can\'t be <strong>Empty</strong>';
            }

            if ($status == 0) {
                $formErrors[] = 'You Must Choose the <strong>Status</strong>';
            }

            if ($member == 0) {
                $formErrors[] = 'You Must Choose the <strong>Member</strong>';
            }

            if ($cat == 0) {
                $formErrors[] = 'You Must Choose the <strong>Category</strong>';
            }

            if (empty($image)) {
                $formErrors[] = 'You Must Choose the <strong>Image</strong>';
            }

            // Loop Into Errors Array And Echo It

            foreach ($formErrors as $error) {
                echo '<div class="alert alert-danger">' . $error . '</div>';
            }

            // Check If There's No Error Proceed The Update Operation

            if (empty($formErrors)) {

                move_uploaded_file($tmpImage, "./items_images/$image");

                // Insert Userinfo In Database

                $stmt = $pdo->prepare("INSERT INTO

        items(itemName, Description, Price, Country_Made, Status, Add_Date, Cat_ID, User_ID, tags, image)

        VALUES(:zname, :zdesc, :zprice, :zcountry, :zstatus, now(), :zcat, :zmember, :ztags, :zimage)");

                $stmt->execute(array(

                    'zname' => $name,
                    'zdesc' => $desc,
                    'zprice' => $price,
                    'zcountry' => $country,
                    'zstatus' => $status,
                    'zcat' => $cat,
                    'zmember' => $member,
                    'ztags' => $tags,
                    'zimage' => $image
                ));

                // Echo Success Message

                $theMsg = "<div class='alert alert-success'>" . $stmt->rowCount() . ' Record Inserted</div>';

                redirectHome($theMsg, 'back');

            }

        } else {

            echo "<div class='container'>";

            $theMsg = '<div class="alert alert-danger">Sorry You Cant Browse This Page Directly</div>';

            redirectHome($theMsg);

            echo "</div>";

        }

        echo "</div>";

I don't know how to solve this error.