PHP Sessions
A session is a way to store information (in the form of variables) to be used 
across multiple pages.
Or
 
The PHP session variable is used to store information about, or change settings for 
a user session. Session variables hold information about one single user, and 
are available to all pages in one application.
Starting with PHP session
For starting a php session use the builtin function session_start(). This 
function is used in the between the php tags, as follow:
<html>
<head>
<title>Session</title>
</head>
<body
bgcolor="orange">
<center>
<h3> 
Starting up a session 
</h3><hr>
<p> 
session_start() 
</p>
<?php
session_start(); 
// start 
up your PHP session! 
?>
</center>
</body>
</html>
Save it as session1.php
Output of the above script
To run the code Open the XAMPP server an start the services like Apache and MySQL. 
Open the browser and type: http://localhost/yourfoldername/session.php  
![s1.gif]()
Storing a session variable
In this section we will use the 
correct way to store and retrieve 
session variables is to use the PHP $_SESSION variable:
PHP script for storing session
<html><head><title></title></head>
<body
bgcolor="cyan">
<center>
<h3> 
Storing the session in the variable</h3><hr>
<?php
session_start(); 
$_SESSION['views'] 
= 1; 
// store 
session data
echo 
"Pageviews 
= ". 
$_SESSION['views'];
//retrieve data
?>
</center>
</body>
</html>
Save it as seevar.php
Output of above script
To run the code, Open the XAMPP server and start the services like Apache and MySQL. 
Open the browser type: http://localhost/yourfoldername/session.php  
![s2.gif]()
PHP session with isset() 
function
Here in this section, session is 
created with the help of isset(). We 
create a simple page-views counter. The isset() function checks if the "views" 
variable has already been set. If "views" has been set, we can increment our 
counter. If "views" doesn't exist, we create a "views" variable, and set it to 1
PHP script 
<html><head><title></title></head>
<body
bgcolor="yellow">
<center>
<h3> 
Storing the session in the variable isset() 
</h3><hr>
<?php
session_start();
if(isset($_SESSION['views']))
$_SESSION['views']=$_SESSION['views']+1;
else
$_SESSION['views']=1;
echo 
"Views=". 
$_SESSION['views'];
?>
</center>
</body>
</html>
Save it as isset.php
Output
To run the code, Open the XAMPP server and start the services like Apache and MySQL. 
Open the browser type: http://localhost/yourfoldername/session.php 
![s3.gif]()
If you hit the same URL again and again the 
counter for session will incremented. 
![s4.gif]()
![s5.gif]()
Destroying a PHP session 
Destroying a session is also a very important part so if you wish to delete 
some session data, you can use the unset() or the session_destroy() function.The 
unset() function is used to free the specified session variable:
<?php
unset($_SESSION['views']);
?>
You can also completely destroy the session by calling the session_destroy() 
function:
<?php
session_destroy();
?>
Note: session_destroy() will reset 
your session and you will lose all your stored session data.
Conclusion: You can use the above given session concepts for your php 
application. Thanks