<?php
// if your url is http://link?var=value
if (isset($_GET['var'])) // works with request
$var = $_GET['var'];
echo $var;
// output value
<a href="index.php?id=<?php echo $my_id;?>&name=<?php echo $my_name;?>Click</a>
<?php
$id = intval($_GET['id']); // integer value
$name = strval($_GET['name']); // string value
?>
<?php
$parameter1 = isset($_GET['parameter1']) ? $_GET['parameter1'] : null;