How to Enable IMAP PHP in xampp

The imap extension comes as standard with the PHP installation. You just need to enable it in your php.ini
 
Enable IMAP in XAMPP:
You need to configure your php.ini file to enable IMAP extension
Search for the line ;extension=php_imap.dll and remove semicolon(;) and restart your xampp.
The line should look like as mentioned below.

extension=php_imap.dll

Note: New php version does not have dll anymore.

The default php.ini should already contain a line to load the extension but commented out:
;extension=imap
Remove semicolon from above like below
extension=imap

Enable IMAP in Linux:
If you are using LAMP server,
First install IMAP using the command on terminal
$ sudo apt-get install php5-imap
To enable IMAP, run the following command.
sudo phpenmod imap
Restart apache server with below command
sudo service apache2 restart