Security Features and Tips
Keep Your Account Secure
Keep your Facebook account secure
Using Security Checkup to add security to your Facebook account
Does Facebook use secure browsing (HTTPS)?
Get a one-time password to login to Facebook
How do I log out of Facebook on another computer, phone or tablet?
Unfamiliar locations in the 'Where you're logged in' section of your Facebook account.
How can I contact the friends I've chosen as trusted contacts to get back into my Facebook account?