The latest iOS comes with a new Safari design that places the address bar at the bottom of the screen by default. Some like this change, but others don't. If you're in the latter camp you can switch back to the classic iOS Safari design with a top bar.
Here’s how to change the iOS 15 Safari address/search bar on iPhone.
While browsing, click on the icon with the two A’s next to the website’s URL, which will open the Safari settings menu.
Tap the option to “Show Top Address Bar.”
Through the Settings app
Open Settings on your iPhone with iOS 15.
Scroll down until you find Safari and tap on it.
Scroll down again until you see the “Tabs” section.
Tap “Single Tab” if you prefer the old style with the address bar at the top.