Downloading Multiple PDF Files

Good day Everyone,

I hope you are all doing well. Please kindly help me, I need to download PDF Files simultaneously by selecting textboxes and clicking on a Download button. For now, I am able to click the Download button next to each item to download the item. I need to have another button which will be used for bulk download of the files.

Below is the code for the Download button next to each item.

<td><a href="print_voucher.php?em_id=<?php echo $row['voucher_id'] ?>" download="print_voucher.php?em_id=<?php echo $row['voucher_id'] ?>"> Download </a></td>
Below is the code for the whole table displaying the items to download.


<form action="createzip.php" method="post">
                        <table id="selection_table" class="data-table table stripe hover nowrap">
                            <thead>
                                <tr>
                                    <div class="col-md-6">
                                    </div>
                                    <div class="col-md-1">
                                    </div>
                                    <div class="col-md-2">
                                    </div>
                                    <div class="col-md-3 pd-10 text-center">
                                        <a class="btn btn-primary" name="createzip" id="createzip" value="createzip"> DOWNLOAD ALL </a>
                                    </div>
                                </tr>
                                <tr>
                                    <th class="table-plus datatable-nosort"> <input id="select_all" style="max-height: 20px; max-width: 20px;" type="checkbox" class="form-control" value="Select All"/> <p> Select All </p></th>
                                    <th> COMPANY NAME </th>
                                    <th> EMPLOYEE NAME </th>
                                    <th> DOWNLOAD LINK </th>
                                </tr>
                            </thead>
                            <tbody>
                                <tr>

                                    <?php
                                    
                                        $sql = "SELECT * FROM vouchers WHERE voucher_id BETWEEN '$empID' AND '$endEmpID'";
                                        $query = mysqli_query($conn, $sql) or die(mysqli_error());
                                        while ($row = mysqli_fetch_array($query)) {
                                        $id = $row['voucher_id'];
                                     ?>  

                                    <td class="table-plus">
                                        <input style="max-height: 20px; max-width: 20px;" name="fieldid[]" id="checkbox<?php echo $row['voucher_id'] ?>" value="<?php $row['voucher_id'] ?>" type="checkbox" class="form-control">
                                    </td>
                                    <td><?php echo $row['paid_by']; ?></td>
                                    <td><?php echo $row['paid_by']; ?></td>
                                    <td><a href="print_voucher.php?em_id=<?php echo $row['voucher_id'] ?>" download="print_voucher.php?em_id=<?php echo $row['voucher_id'] ?>"> Download </a></td>

                                </tr>
                                <?php }?>
                            </tbody>
                        </table>
                    </form>

Please help me to download the files simultaneously.