If you think that someone else already knows your password, or if you’ve think that the current one just isn’t secure enough, you should change your Facebook password. Following these steps, you can accomplish this quickly and easily.
1. Go to Facebook and login to your account.
2. Go to the right side of the menu bar and select Settings.
3. The My Account page will appear. On the Settings tab, go to the Password section and select the change link.
4. Input your Old Password (the current one). Input your New Password and input it once again to Confirm it.