2FA or 2 Factor Authentication is an extra layer of protection to ensure the security of your account in addition to your username and password.
To enable 2FA:
1. Go to "My account"
2. Select "Security" from the panel on the left.
3. Download the app appropriate for your phone and click "Next"
Open the app on your phone and scan the QR code on the screen. Make sure to save the recovery key as well. You will need the key to reset your 2FA if you change your device.
Enter the code from your phone on the next screen and your 2FA will be enabled.