Magento 2 Two-factor authentication uses Google Authenticator OTP.
Google Authenticator works with 2-Step Verification for your Google Account to provide an additional layer of security when signing in.
Enable Two-factor authentication for admin customer
Enter your OTP code on login page
Install module. Run in masgetno root follder
composer require somelchenko/gauthenticator
bin/magento setup:upgrade
Disable two-factor authentication for customer
bin/magento admin:user:disable-google-otp
There are also older open source versions of the Google Authenticator app for both iPhone and Android.