There are two different ways to enable inprivate browsing for Mozilla Firefox.
This method is optimal for users who want Private Browsing mode for the browser they are using just at that time. It will revert to the normal interface once you exit out of Mozilla Firefox.
Launch Mozilla and navigate to Firefox menu and select Start Private Browsing.
A notification box appears stating that Firefox will save your current tabs when you are done with inprivate browsing. Click Start Private Browsing to continue.
Note: You can also tick the don’t show this message again if you prefer not to receive this alert every time you turn on Private Browsing.
The Private Browsing information screen appears to inform you that you are in Private Browsing mode and the Firefox button on the top left will become purple.
This procedure will enable Private Browsing to be on permanently in Mozilla.
Launch Mozilla and navigate to Firefox menu and select Options from the drop down menu.
Navigate to the Privacy tab. In the History section, set Firefox will: Use custom settings for history from the drop down menu.
Tick the box Always use private browsing mode. Select OK to save changes and exit out of Options.
Mozilla will now surf the internet in an inprivate browsing mode but appearance will look like it is in the original browser interface (i.e. the Firefox button will not turn purple).