By default, Safari saves any webpage you visit to you browser history, and makes them available to all your other Apple devices via iCloud Tabs. If for any reason you don't want certain sites you visit to get saved to history or made available to iCloud Tabs - we don't judge! - you can quickly and easily enter Private Browsing mode. Switching to Private Browsing mode will also prevent websites from tracking you with cookies, and autofill from saving or completing any of your personal data. What's more, iOS 7 makes it easier to access than ever before.
Note: To disable private browsing, just repeat the same steps again.