Add the following code in your site, inside the head tag:

<script>
        function SocialShare(url) {
            window.open('https://www.exoltech.us/share?url=' + url, '', 'height=600,width=800');
        }
    </script>

Then place the share button after changing the URL you want to share to your page HTML:

<button onclick="SocialShare('http://yoursite.com/')">Click me</button>

Example: