Active Domain in CDN

To transfer a domain it should be active on Cloudflare CDN/DNS service?
Kind regards,

I do believe that’s the case.

As far as I remember for my two .com TLD domains, I already had them added to my Cloudflare account and when I was transfering them from ex registar to Cloudflare registar, no further action was needed regarding the change of the nameserver records (as they were already under my CF account) to Cloudflare ones as far as the EPP code was given in the process to the Cloudflare and the whole transfering process was successfully completed in a few days.

Furthermore here: