Chrome will show security warnings

I got the following message from google to my webmaster account email:

“Starting October 2017, Chrome (version 62) will show a “NOT SECURE” warning when users enter text in a form on an HTTP page, and for all HTTP pages in Incognito mode.

The following URLs on your site include text input fields (such as < input type=”text” > or < input type=”email” >) that will trigger the new Chrome warning. Review these examples to see where these warnings will appear, so that you can take action to help protect users’ data. This list is not exhaustive.”

And they display some links from my site. What is this and what must I do?