The "not secure" message you're seeing is because your site doesn't have a what's called an SSL certificate, which is an extra level of encryption designed to protect data.
Due to the nature of the AgentID Site -- in that it does not produce any type of e-commerce -- an SSL isn't traditionally necessary. However, if you'd like to add it to your site, you certainly can.
CloudFlare offers a free SSL you can add to your site from this page: https://www.cloudflare.com/ssl/
You'll need to create a CloudFlare account, then follow the steps instructed in the wizard.
CloudFlare's help center, should you have any trouble, can be found at https://support.cloudflare.com/hc/en-us
Here is also a guide we created to assist with the basic setup of Cloudflare: CloudFlare Name Server Access