when i try to post any on forum mostly it shows"Post hidden by community flags" after some time latter
Perhaps you´ve accidentally done something that is against the forum rules, there are quite a few.
If someone from the community flags a post, the forum moderators will get a notification and look at the post when they get around to it and will decide if the flag is valid, then the post will remain hidden; if they decide the flag was invalid, they´ll defer the flag(s) and the post will become visible again.
Usually, I think it takes several flags to hide a post, so if you often get posts hidden, maybe you´d like to read the forum rules and etiquette to know what it is that gets your posts flagged so often:
I noticed most new users get flags if they are off topic. For example, they try to advertise their Fiverr gig in a thread.
Because you write on the wrong section