How to create plugin for Admin Category Settings

[leonor]

Hello i need a extra field in my Category settings, for every Category.
Because i want to display in every category some extra lines.

But i don't know any plug in hook for this area and i don't know where i have to search.

Any one have a idea i can create something like this?

greetz,

leonor

EDIT: Ok ... i need to edit the plugin SEO :/