The incognito search feature allow you to web search privately .This feature is already present in chrome and safari browsers but now Google will provide you the ability to search in incognito mode. This feature is added in an update to the Google app.
It’s a small but helpful change. The more interesting part of the update isn’t incognito mode on its own, it’s how Google is making them even more secure. Google will let you lock up private searches using Touch ID, so that if someone else is holding your unlocked phone or tablet, they won’t be able to see private tabs that are still open inside the app.
In addition to incognito mode, new update also includes the ability to watch YouTube videos directly in the app.