The submit(update) button return an empty value, causing the update function not working

Currently doing the address part in e-commerce website application. The address needs to be edited. I have included the SQL query and PHP code well, but still can’t run. There is no error message prompt. Below is my part of the code:

As there are multiple addresses, each address has an edit and delete button. The edit button will do the editing work based on the address-id passed inside.

<?php
                    while($row = mysqli_fetch_array($address_result_query)) {
                        $address_id=$row['address_id'];
                        $_SESSION['address_id'] = $address_id;
                        echo "<td>
                              <a class='editbutton' href='editaddress.php?
                              address_id=".$address_id."'>Edit</a>
                              </td>";
?>

On the edit page, it will show the address data currently, and allow the user to modify it inside the text box. Below is the code to get the user data.

    <form  name="update_" method="post" action="editaddress.php" >
            <?php
            $address_id = $_SESSION['address_id'];
            $result2 = mysqli_query($mysqli, "SELECT * FROM user_address WHERE address_id='$address_id'");
            $row2=mysqli_fetch_assoc($result2);
            if(isset($row2['address'])!=null){
                $address = $row2['address'];
                $state = $row2['state'];
                $city = $row2['city'];
                $postcode = $row2['postcode'];
                $address_name = $row2['address_name'];
                $address_phone = $row2['address_phone'];
            }
            ?>

Code to show the data:

<div class="container_header">
                    <p>Edit Address</p>
                    <br>
                </div> 
                <label>Recipient Name:</label>
                <br>
                <input type="text" size="50" class="address_name"name="address_name" value="<?php echo $address_name;?>">           
                <br><br>

                <label>Recipient Phone:</label>
                <br>
                <input type="text" size="50" class="address_phone"name="address_phone" value="<?php echo $address_phone;?>">
                <br><br>

                <label>Recipient address:</label>
                <br>
                <input type="text" size="50" class="address"name="address" value="<?php echo $address;?>">
                <br><br>

                <input type="text" size="50" class="state"name="state" value="<?php echo $state;?>">
                <br><br>

                <input type="text" size="50" class="city"name="city" value="<?php echo $city;?>">
                <br><br>

                <input type="text" size="50" class="postcode"name="postcode" value="<?php echo $postcode;?>">           
                <br><br>

                <input type="button" onclick="location.href='index.php';" name="add_address" value="Cancel" class="cancel">
                <input type="submit" name="update_address" value="Update">
            
    </form>

When user click on the update address, below PHP will run, but it’s not. The code are inside the edit page, same location with above

if(isset($_POST['update_address']))
{   
    if(isset($_POST['address'])){
        $address = $_POST['address'];
    }else echo"address not get";
    $address_id = $_POST['address_id'];
    $state = $_POST['state'];
    $city = $_POST['city'];
    $postcode = $_POST['postcode'];
    $address_name = $_POST['address_name'];
    $address_phone = $_POST['address_phone'];

    $myquery = "UPDATE user_address SET 
                address='$address',
                state='$state',
                city='$city',
                postcode='$postcode',
                address_name='$address_name',
                address_phone='$address_phone'
                WHERE address_id='$address_id'";    
    $result = mysqli_query($mysqli,$myquery)or die(mysqli_error($mysqli));
    
    header("Location: ../profile/index.php");
}    
?>