iOS 15 introduced a redesigned Safari interface that places the address bar at the bottom of the screen. If you prefer to keep it at the top of the screen — like most web browsers — that can be easily changed.
See also: Chrome, Firefox, Safari, Edge & Brave: What settings to change to enhance privacy?

See also: How to allow pop-ups in Safari on Mac
There are a few advantages to having the address bar at the bottom. First, it's easier to navigate with one hand on a large screen. Second, it puts all of your browser controls in one place. If you're not yet convinced to try it, we can't force you, but we would recommend it.
First, open the Settings app from the home screen.

Scroll down and select “Safari”.

Go to the “Settings” section and switch to “Single Tab”.

There you go! The address bar is back at the top of the screen, and the other browser controls are still at the bottom.

See also: iPhone/iPad: How to delete recent History in Safari?
Regardless of which interface you prefer, the same amount of content is visible, so it's just a matter of what feels most convenient to you. Apple , of course, seems to continue to make changes and add features to Safari.
Information source: howtogeek.com
