Is it possible to publish the cameras, and the public can access directly to a link without introduce passwords or emails or download software?  i mean total free access!

Yes. The "Publish Camera" feature is documented in this support page:

https://www.cameraftp.com/camera/knowledgebase/howtoPublishCamera.aspx

You can publish a camera on CameraFTP.com website; you can embed a published camera in your own web page, and you can also use the "Get Last Camera Image" URL (in your own web page or program).