Licence transfer

Dear Sirs,
I am a graphic designer and “inherited” a WordPress website that I didn’t create or administer from one of my clients due to the passing of his former webmaster. As a web designer, I did many projects but always skipped WordPress for several reasons. I’m now slowly getting familiar with the project and did some updates, running into smaller issues with the used theme Enfold/Enfold Child (apparently, a cjhild theme had been created and is being used). I now wanted to put some questions into your forum and thatfor wanted to register for being able to post.
The registration process requires a licence code that I do not have, nor does my client. Is there any way to find the licence code within the running installation or, if this is not possible, any other method to register for your support forum?
Thank you very much for any suggestion on how to proceed.
Kind regards
Attila Sirman, Munich, Germany