Category dropdown not showing

On my website (https://www.berekenhulp.nl/kennisbank/) the category and tags dropdown is not showing.

Is it possible to change text, for example “catogorie” on the same page (https://www.berekenhulp.nl/kennisbank/)

Is it possible to add the “ask a question” form to every other page on the website?

Is it possible to add a category page to every other page on the website?