If you have it registered as an authenticator in your Org and a user has it registered as one of their authenticators and the application authentication policy allows it then it should show up as a remediation option.
Have you already setup Duo in your Org and verified that it is allowed for your apps authentication policy?
I have it setup correctly on my org with the policy and everything . And it shows up as an option however i can’t get it to work on Embedded Auth .
I get this message when trying to use the Duo option - “Required parameter signatureData missing"
However upon inspection to the response from the SDK i see that it contains contextualData object with all the relevant data inside of it but it’s not publicly accessible , this makes me think there must be another way to complete the Duo flow .