Two-Factor Authentication (2FA) is way to add an extra layer of security to your account. There are several authentication applications to choose from. Google Authenticator and Authy are the most popular.
To enable this feature:
Navigate to the Profile Menu and select the Two-Factor Security option under the Security menu.
A prompt with a QR code or unique code will populate to enter into your authentication application.
Enter the code that is given and sync.
You will be given a 10 unique list of codes to recover your 2FA should you lose access to your authenticator. Save these in a safe place should you need to recover your 2FA on another device.