Moving to HTTPS
To have HTTPS, SSL Certificate is needed to be installed on the server. Another option is to use Free CloudFlare SSL
After activating ssl, edit the file system/config.php and update the url, change http to https
If https is available before installing & you use https when installing, you are already using https & you do not need to change anything.
Why Use HTTPS?
All websites without a valid SSL certificate shows notification- "Not Secure", started from July 2018 with the release of Chrome 68. Moreover, you should always use business suite with HTTPS as it has login, authentications etc. & HTTPS protects the privacy and security of your users.
Still stuck? Open a support ticket.