https://wccftech.com/how-to/how-to-automatically-close-all-open-safari-tabs-on-ios-13/

Apple has overall improved its Safari browser on iOS 13. The company is gradually making changes in the platform which will ultimately enhance utility for the end-user. With iOS 13, Apple has added several new changes in iOS 13 including the ability to automatically closing all opened Safari tabs. See the step by step instructions below on how to automatically close all Safari tabs in iOS 13.

Once you’re done with acquiring certain information from the web, you close the Safari app. However, the tab remains open in the background and the next time you visit the browser you are greeted with a handful of useless tabs which you have to manually close.