You can use the $_SESSION super-global to achieve this.
$_SESSION['Email'] = 'example@example.com';
That would make that variable accessible on multiple pages provided you support sessions within your code.
To do that, on every page you want to access the session values you would call
session_start();
and after you have called that, you can go ahead and access the variable you set elsewhere.
echo $_SESSION['Email']; // Outputs example@example.com