You can enable the moderation of posts on
Admin ---> Spam ----> "Use moderation for users with few points"
If you want to enable it for all the users, you should set a high value in the "points" textfield (there is not an option to enable it for "everybody").
It will be enabled for all the posts on all categories (do you mean "category" when you write "section" ?)
If you want to move a post to the moderation queue only if it belongs to some categories, you should write a plugin (using a filter module ; see this post as an example).
In the Admin panel you have a "Moderate" submenu item that links to the moderation queue, where a moderator level user will can approve or reject the post.