Whether HTTP or HTTPS is used is up to the server - WebEasy does not know (and does not care) whether the site is to be accessed via HTTP or HTTPS. Depending on how the server is set up, it may be as simple as publishing the site normally, then typing in "https://www.mywebsite.com/" (or whatever) to access the site, rather than http://www.mywebsite.com/
Alternately, if you just want a certain part of the site to use HTTPS, you will probably have to make two separate WebEasy sites, and publish them to separate folders on the server, then use the "link to www site" option to link from the non-secure site to the secure site (e.g.: a link to https://www.mywebsite.com/secure/). The server will have to be set up to allow HTTPS access to the secure folder.