HTTPS across all pages

Hi, I have a question. I have two sites with SSL certificates. One has https across all the posts and pages, while the other one only has http. I have looked inside wpconfig and htaccess site on the site that has https, and I cant see any code that will force https. My question is, why does https show up on a site and another it doesn't? The site that has https is a multisite. Where in general settings do I put in https? I really cant remember how I got https to work on that site :slight_smile:
Kind regards, Ingie