The incognito tab is where you can browse the internet privately with no search history or Safari remembering and keeping any thing. To open an incognito tab on iPhone, iPad and iPod Touch devices and surf the web privately, do as follows:
1. Open the Safari application on your iPhone
2. Tap the Tab button in the bottom right (It's icon is like two rectangles)
3. Hit the Private button in the bottom left
4. You just entered the Private Browsing Mode, where you can view websites without worrying about any history or else. This incognito mode is the best for those who need to login to their emails via a friend's iPhone.