Multitasking and using two apps on the iPad at the same time isn't new for iOS 10, but the option to use two Safari windows at the same time is. With iOS 10 you can load up a split view of two web pages in iOS 10 at the same time. This makes it possible to comparison shop, look up multiple things at the same time and be more productive on the web.
With Safari for iOS 10 on iPad you can open up two Safari windows next to each other with an address bar, tabs and bookmarks in each. it is possible to move a tab from one side to the other.
Unlike the other apps that you can use side-by-side on the iPad, you cannot adjust the size of these windows. This only works on the iPad Air 2, iPad Pro 9.7 or iPad Pro 12.9.