If you have opted to save logins and passwords for the sites you visit, there may be times when you wish to delete that information for a particular site. Here’s how.
Begin by clicking on the hamburger menu icon at the far right of the toolbar and selecting Options.
In the screen that appears, select Privacy & Security.
Select Saved Logins…
Scroll to the site that you need to delete.
Click Remove, then Close.
Firefox also provides an option to import passwords from Google Chrome and Internet Explorer. In the screen above, click the Import… button and follow the instructions.