Many people keep important personal information on their Facebook accounts, such as their full name, address and work place. Even if you customize your profile so that only accepted friends may see these details, someone could hack into your account and not only see your full profile, but also read all of the private messages that you send out and receive. To prevent this from occurring, change your Facebook password regularly, and never give it to anyone else. If only you know your password, only you can view your Facebook messages.
Go to your Facebook homepage. Look in the upper right corner of the screen and find the account link. Click on this link.
Look at the choices in the drop-down menu. Scroll down and select account settings. A new menu will appear.
Locate the password heading on the new page. Look to the right and find the blue "change" link. Click on this link.
Fill out the form to change your password. Click the "change password" button to confirm the change. Sign out of Facebook and sign in again with your new password to test it.