<?php
$user='root';
$password='';
$conn=mysqli_connect('localhost',$user,$password);
mysqli_select_db($conn,'4iagr1');
$result=mysqli_query($conn, "SELECT * FROM klienci");
$num= mysqli_num_rows($result);
echo '<form action="conn.php" method="POST">';
while ($row=mysqli_fetch_assoc($result))
{
    $id=$row['id'];
    $imie=$row['imie'];
    echo "$id $imie";
    echo "<input type='submit' name='XD$id' value='usun'><br>";
    $sql = "delete from klienci where id = $id";
    if (isset($_POST["XD$id"])) {
        mysqli_query($conn, $sql);
    }
}
echo '</form>';
mysqli_close($conn);
?>