How to Turn On Login Notifications in Facebook ?

Login Notifications are an opt-in security feature where alerts are sent to you each time your account is accessed from a new device.

To turn on Login Notifications:

1. Go to your Security Settings page (Account > Account Security > Security)
2. Click on the Login Notifications section
3. Check the box next to the type of alerts you’d like to receive and save your changes

Note: If you want to receive text message alerts, you’ll need to add a mobile number to your account.

After you turn on Login Notifications:

• We’ll ask you to name your computer or mobile phone next time you log in. You can also save this device to your list of Recognized Devices. This way, you won’t have to keep naming the computer or mobile phone you usually use to log in to Facebook.Note: Don’t select the option to save your device if you’re using a public computer.
• When you name a device, we’ll send a notification to the email address associated with your account and your mobile phone, if you selected that option.
• If you ever receive a Login Notification from an unfamiliar device or location, follow the instructions in the notification to reset your password and secure your account. [source]