In the Sage HR app you can enable identity verification so that when you log in, you're required to verify yourself. This is the same way you unlock your phone.

Depending on your phone this could be your face or fingerprint authentication. If you're asked to enter something, this would be your phone's PIN or passcode, i.e. the number you enter to unlock your phone normally.

If you no longer want to use this identify verification, you can switch it off following the same steps outlined in, Enable identity verification.