We would like to understand what is the difference b/w Visual application and Application extension

Summary:

Hi Team,

(i) We would like to understand what is the difference b/w the New Visual application and New Application extension in workspace . It will be under Navigator » Configuration» Visual Builder. Please find the below attached screenshot. will it requires any license?

(ii) and also I can't able to see the "Publish" Option in the visual application work space where I have created a page in it. Did anyone known's about it? and also will that require' s license?

Thank you so much for your support!

Regards,

Mahesh