How to store a variable in php using session

Question

i want to store a value in to session using PHP

for example $id=10 i want to store this value in a session

i tried

$pid= session_id($id);

echo $pid;

and

$pid = $_SESSION['$id'];   

but not working

Answer 1

at the top of page

session_start();

then to set session variable

$_SESSION['id'] = $someID;

To retrieve the value of id

$pid = $_SESSION['id'];

Further more read more about session here