Hi vikasnautiyal18.
With CEM (Cloud-Enabled Management) configured in your enviroment, yes, it's possible to manage all you computers over the internet. You can install software and patches, collect inventory, etc.
To be possible do the activities above, you will need a server in your DMZ, but the configuration it's quite easy to do. You will also need a certificate (you can generate one using your own Altiris or use a third-part certificate) and configure your agents to connect via https (You can configure that on Targeted Agent Settings).
The link bellow shows you how to do all the configurations about the CEM funcionality. Also i'm attaching a link with all documentation about that.
Video
https://www.youtube.com/watch?v=v9aT1TnDNVw
Documentation
https://support.symantec.com/en_US/article.TECH227638.html
Regards,