Private browsing in Safari allows a person to browse the Web without storing local data that could be retrieved at a later date. To disable browsing history and the web cache in Safari, do the following:
Step 1: Along the top of the screen, when you have safari selected, click on the File tab.
Step 2: Select the second option in the menu New Private Window
Step 3: Once clicked on, a new window will appear. You can tell which browser is the private browser by looking at the URL bar. The URL bar in the private window will be darker than the standard browser.
Now you can browse the internet without anything done previously in Safari affecting websites.
When you have finished browsing, as soon as you close the private window, all your browsing history and/or credentials you have used will be wiped.