What is a cookie , explaing ?

Cookie is use to store the temporary data in browser memory, We can store data in cookies using setcookie('name','value','time');
we can use that rule for simple cookie, this value will store in the browser memory. If the browser is closed the cookie value will be deleted. Another way to store data in cookie file for long time:
persistent cookie using that way we can store data for long time in the user system.