To enable 2FA for your Pro Backup account:
Go to go to https://app.probackup.io/settings/account
Click on Enable 2FA.
This will open a popup with a QR code and a secret code.
Either scan the QR code with your 2FA app or copy-paste the secret code in your 2FA app.
Fill in the 6 digit code that you've received from the 2FA app
Click on Enable 2FA to complete the process