setcookie(name, value, expire, path, domain);

<?php
setcookie("user", "Alex Porter", time()+3600);
?>

<?php
$expire=time()+60*60*24*30;
setcookie("user", "Alex Porter", $expire);
?>
<html>

In the example below, we retrieve the value of the cookie named "user" and display it on a page:
<?php
// Print a cookie
echo $_COOKIE["user"];

// A way to view all cookies
print_r($_COOKIE);
?>

In the following example we use the isset() function to find out if a cookie has been set:
<html>
<body>

<?php
if (isset($_COOKIE["user"]))
echo "Welcome " . $_COOKIE["user"] . "!<br>";
else
echo "Welcome guest!<br>";
?>