Choose the Authenticator/Mobile App option when signing up for two-factor authentication.
If the instructions describe using Google Authenticator or any other type of authenticator app, you can go ahead and use Duo instead.
Here is Duo’s documentation on the subject.
IMPORTANT: Please be sure to enable the restoration function for your accounts so if you get a new phone or number they can be restored.
*Note: these are passcode only, push is not available
LastPass – https://support.logmeininc.com/lastpass