How do I use CkEditor layout on textfield input? I have a content type with a "Text (formated)" field. When I try to write something in it, all my HTML is ok. But I want to use the buttons of ckEditor to make it more "user friendly". I don't want to always have to write all my tags manually.

On "Text, long (formated)" field, there is no problem.

You can see what I mean in this screenshot. 



I already tried to switch text format under my field. Nothing changed, except I got more tags allowed.
CKEditor only works on a textarea, you can’t attach an instance to a textfield. 

You could implement hook_form_alter and change it from a textfield, but it’s hard to see what the point would be.

If you need long text, just use a long text field. It was designed for your use case, so will always work as expected.