PHP:How to echo description from HTML Input tag after doing array [duplicate]

Firstly sorry if the title make some of you confuse ... here's the real problem.

I am developing a system that generates a receipt from HTML Form. The real problem is that I don't know how to get all descriptions because I'm using multiple input controls on the form.

In add.php, there are some description boxes where staff can enter the purchased info. I'm using Input. The code's are:

<input type='text' name='desc[1]' size='40px'><!-- (I'll copy paste it 9 times) -->

This is the only place to enter all info, then it will redirect to view the order info.

I can echo everything using $_REQUEST, but I don't know how to echo this. People say it's an array but I don't understand it that much.

Here some code:

Add.php

<?php

include 'server.php';
session_start();
$id = $_SESSION['id'];

if (isset($_POST['submit'])) {
    $order = $_POST['order'];
    $name = $_POST['name'];
    $tel = $_POST['tel'];
    $orderdate = $_POST['orderdate'];
    $firstfit = $_POST['firstfit'];
    $event = $_POST['event'];
    $desc = $_POST['desc'];
    $color = $_POST['color'];
    $address = $_POST['address'];

    $syntax = "INSERT INTO `client` (`order`,`name`,`tel`,`orderdate`,`firstfit`,`event`,`desc`,`color`) VALUES ('$order','$name','$tel','$orderdate','$firstfit','$event','$desc','$color')";
    $insert = mysqli_query($config, $syntax);
    header("Location: do.php");
}

Then here's the input

<tr>
    <th>DESCRIPTION :</th>
    <td>
        <input type="text" name="desc[1]" size="90px"><br>
        <input type="text" name="desc[2]" size="90px"><br>
        <input type="text" name="desc[3]" size="90px"><br>
        <input type="text" name="desc[4]" size="90px"><br>
        <input type="text" name="desc[5]" size="90px"><br>
        <input type="text" name="desc[6]" size="90px"><br>
        <input type="text" name="desc[7]" size="90px"><br>
        <input type="text" name="desc[8]" size="90px"><br>
        <input type="text" name="desc[9]" size="90px"><br>
    </td>
</tr>

So how can I echo out all the 9 different descriptions into the receipt? I'm sorry if this question is not clear because I'm still a beginner :-(