How to enable pinch zoom on website for mobile devices?

Hi,

You can change meta tag on to header.php file: http://prntscr.com/np687q

From: 

 <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">

To:

<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=12.0, minimum-scale=.25, user-scalable=yes">

Thank you