Change PHP version 5.6 to 7.x in WampServer 3

1.  Click on WampServer icon in right side bottom taskbar
   
2. Select the PHP menu ->Version  from the Pullup menu box.
   
3. Check the version via browsing http://localhost or via command line typing following command

   php -version

   

4. Done !

Recommended Readings:

https://planetthemes.com/how-to-change-the-www-root-directory-on-wampserver-3/