Textarea Custom Category Field

Hi everybody,

I am making a textarea custom filed for the category ( with wp_editor also ). Everything is working, but I have only one problem. I don’t know the filter to run with the content before save it. In fact I have a lot of problem with the formatting of html. I would like to use the exact process that WP uses with normal content inside a post.
Also, I would like to know the filter before echo it, both in the textarea and the front end.

Thanks a lot for helping!