If you're talking about url/search bar at the bottom on mobile, that's customisable - actually they ask you which you prefer when you install it, but you can change it at any time in settings. (personally I prefer all that stuff at the bottom since it's more conveniently where all my other phone nav is, and visibility fits in well with how I scroll)

I mean on the computer, and I haven't found a way to have it at the top.

Alright, now I'm doubly confused, since the search bar is typically on the address bar which is at the top of the screen. You might want to test a clean profile. Perhaps some customisation along the way changed things on your setup.