In order to have your website through secure connection (https): 

Step 1. First you'll need to purchase the SSL certificate (or use free 90 days certificates).
We usually suggest SSL certificates from Godaddy. 

After you get the certificate, you'll need to generate it and install it. Here is Godaddy's guide using cPanel: https://godaddy.com/help/installing-third-party-ssls-on-cpanel-accounts-12027

Step 2. When the certificate is successfully installed: in the root folder -> config.php
Find define("SITE_SERVER", "http://sitename,com/");
and change it to define("SITE_SERVER", "https://sitename,com/");

Then in the .htaccess file add redirect from http to https right after RewriteEngine on:
RewriteCond %{HTTPS} off
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
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