How does Firefox erase my personal private data

Firefox if you want to erase all of your private data, you can use the tools-clear private data, select which categories you want to erase, and then click the "Clear Private info Now" button. Note that this method will clear all private data in the appropriate category you selected. For example, if you select a saved password, the password for all sites you save under this profile will be cleared. If you just want to erase individual private data, you should use the tools-options-privacy, through the tag to select the type of private data you want to work with. History, saved forms, caches can only be cleared, passwords, download histories, and cookies can be individually purged by viewing the interface.