<form action="index.php"  method="post">
<?php for($i = 1; $i <= 15; $i++){?>
  <input type="text" name="veri<?=$i;?>[id]" placeholder="ID">
  <input type="text" name="veri<?=$i;?>[ad]" placeholder="Adı">
  <input type="text" name="veri<?=$i;?>[email]" placeholder="Mail Adresi">
  <input type="text" name="veri<?=$i;?>[nr]" placeholder="nr">
  <br><br>
<?php }?>
  <input type="submit" value="kaydet">
</form>
<pre>
<?php
if($_POST){
foreach($_POST as $ant => $veri){
    if($veri['email']){
    $query     = $db->prepare("INSERT INTO tablo SET id = ?, ad = ?, email = ?, nr = ?");
    $insert = $query->execute(array(     $veri['id'], $veri['ad'], $veri['email'], $veri['nr']));
    }
}
}
?>