Your company has enabled multi factor authentication (MFA) for your account.
See the Knowledge Base for more information
To login you will need to select an authentication method (Email or Authenticator App)
You will occasionally be asked to reauthenticate at login.
For email you will need to request a code to be sent to your email address.
For the app you will need to have installed an authenticator app (e.g. Google's or Microsoft's authenticator apps) then use your authenticator app to scan the QR code.