After setting up https, www.mywebsite.org still defaults to http. How can I make https the default?

I have set up https for my website using Cloudflare.   Now https://mywebsite.org and http://mywebsite.org both work properly (one is a secure connection the other not).   Excellent.  However mywebsite.org and www.mywebsite.org still default to the non-secure version.   How can I change that?