• Enable VirtualHosts
    • The first thing you’ll need to do is open the file /Applications/XAMPP/xamppfiles/etc/httpd.conf in your favourite text editor. Look for the following lines:
    • # Virtual hosts 
    • #Include /etc/httpd-vhosts.conf
  • Replace /etc/httpd-vhosts.conf with /Applications/XAMPP/etc/extra/httpd-vhosts.conf and Uncomment the second line by removing the hash (#), so that Apache loads your custom VirtualHosts configuration file.

Follow exactly the following page.

https://www.drupal.org/docs/7/multisite-drupal/multi-site-on-windows-using-xampp