Facebook – get page id with/without access token – Facebook api

Their is a way to get a facebook page id via get request? Or i need to send also a access token ?

For the second option. I have a facebook application. How i can get the facebook page id?

I use this code (Extracting page id from a facebook page url):

$fbUrl = "https://www.facebook.com/Lo-stile-di-Anna-
1521824524722026";
$graphUrl = "https://graph.facebook.com/?id=".$fbUrl."&access_token=xxxxx&fields=id";
$output = file_get_contents($graphUrl);
$output = json_decode($output, TRUE);
echo $output["id"]; // returns 1521824524722026

As you can see i need the access_token parameter. How can i obtain it automatically (via script call) or how can it stay permanent?

Thank you!