Good to know.
As of July 1, 2019, Microsoft will no longer offer MFA Server for new deployments. New customers who would like to require multi-factor authentication from their users should use cloud-based Azure Multi-Factor Authentication. Existing customers who have activated MFA Server prior to July 1 will be able to download the latest version, future updates and generate activation credentials as usual.
The on-premises version is available for download here:Azure Multi-Factor Authentication Server
To setup and use Multi-Factor Authentication in Azure, see:Planning a cloud-based Azure Multi-Factor Authentication deployment