Like if a people want help me with a game,what i need do to allow him to edit too?

Is there proper multi-edit on the web editor yet? If not I Imagine you'll have to share passwords, never really a good idea.

Probably a better idea is to set up distributed source control, like on Github and Bitbucket, and work with the desktop editor. If you're not familiar with programming that'll take a little setup, and maybe isn't what you want anyway?