How to hide category name

Hello.
I have created menu with categories (because I want “pages” with posts).
Problem is that I want to hide category name, which display on top of page.
I have tried to hide it with help of CSS, putting codes which found in internet, but nothing helped. I have 4 categories like this which names I would like to hide.
Probably that’s not hard and I hope that someone could help me.
If needed that’s how categories showing looks like https://www.myreldiary.com/category/free-time