[تم الحل] support for attributing language

Background of the issue:
Hi, I would like to understand how to activate WPML also in my Custom Post Types pages. I also installed the necessary plugins but I can't see the translation flag as in the pages. The site I need help with is الرابط المخفي.

Symptoms:
I can't see the translation flag in my Custom Post Types pages.

Questions:
How do I activate WPML for Custom Post Types pages?
Why can't I see the translation flag in my Custom Post Types pages?