Cloudflare’s Origin Certificates are not valid certificates. Cloudflare is not a recognized SSL vendor, so their “Origin Certificates” cannot be uploaded. To use Cloudflare on your site, you can configure Cloudflare to use “Full” SSL mode in conjunction with the default certificate, which also ensures your connection is encrypted the whole way. If you insist on using “Full (strict)” mode, you must use a regular SSL certificate for your site instead.
You dont need to verify from cpanel or upload any certificates, go to dash.cloudflare.com then select your desired site, then select SSL/TLS option then choose flexible mode and then go to edge certificates option and turn on “Always use https” option. Then it should work.
I would like to note: if you change then the settings of your WordPress to have HTTPS URLs, that option might cause a redirect loop. It’s better to set the SSL option to “Full” instead, because it then causes the website to work with both protocols applied on the URL, not just with HTTP, and it increases the security level by combining Cloudflare’s certificate with the default self-signed one instead of letting Cloudflare connect to the server via HTTP only.
@ThosCo flexible setting on cloudflare can make your website having a redirect loop. I recommend you setting it on FULL. As I see there on your website you have everything setup correctly. The SSL is showing, but you have a little problem, please select this on your dashboard under SSL/TLS > Edge Certificates: