Fixed floating menu next to the head

I see more and more websites but also various apps that have menus (three lines) that remain fixed when you scroll the page.

How can I deal with this issue to enable this feature?
I wish the menu, as I see it now, but I want to keep a fixed upwards.

Finally, how do I move the menu from the right to the left box as they do all?

I specify that I’m talking about the mobile viewing

Thanks a lot