That's because FANDOM Staff removed the feature due to vandalism in the wiki. In that case, only registered users are allowed to edit the wiki. If you want to have that "anonymous feature", please contact the Staff at Special:Contact/general.
That or your admin of the community we can enable or disable the feature of that community depending on which of course. If we're not admin of the community wikia wiki or fandom your on contact your local admin hope it helps.