what is the full forum on LINUX?

Methinks you are going to have to explain that question, as it isn't immediately clear what it is you are asking.

I agree. You need to explain your question.

That said, "Linux" is a big topic with use being from very small embedded boards, servers, user workstations and what else. The topic is so broad that not only what Linux is being used for matters but what distro you are using along with what issue or topic you want to breach.

If you want to talk distros talk about debian/ubuntu. Almost everyone know those. The others are rare. The best one for newbies is Linux Mint. The best one for computer hackers is Kali. IT people like parrot also.