Logging On with Duo
Users log on as usual with their regular username and password. If primary authentication succeeds, the user is presented with authentication methods in the Duo Prompt.
The specific authentication methods available depends on the type of device the user has registered, and what policy you have configured in Duo. You can read more information about the policy here: https://duo.com/docs/policy.
For an in-depth guide on how to use the Duo Prompt, go here: https://guide.duo.com/prompt.