Duo Push is a two-factor authentication (2FA) method provided by Duo Security. Instead of entering only a password, users receive a login approval request ("push") on the Duo Mobile app installed on their smartphone.
To use Duo Push as 2FA authentication, an application must first be configured at duo.com and the credentials stored in your system.
Optionally, you can enable "Verified Duo Push". Users must then enter a 3-digit code for safer verification. You can adjust the policy in the Duo Admin Panel: