Setting up Cloudflare to only use HTTPS is pretty straightforward:
- Login to Cloudflare >> select the site
- Go to SSL/TLS tab >> Edge Certificates
- Turn ON "Always Use HTTPS"
The other way is to use page rules.
- Go to Page Rules
- Click "Create Page Rule"
- Enter the URL (put the asterisk, so all URLs are redirected)
- Click "Add a Setting" and select "Always Use HTTPS" from the drop-down
- Click "Save and Deploy"
After a few minutes, all URLs will be directed via HTTPS. Check your site for mixed content (HTTPS vs. HTTP); having HTTP assets will cause your site to break.