For testing or if you lack immediate access to the portal, you can download the Windows Server 2019 Evaluation ISO .
Microsoft protects its Volume ISOs behind authentication (login to VLSC or Visual Studio). You cannot legally bypass this. If you do not have a Volume License agreement, you must use the Evaluation Center ISO or purchase a license. windows server 2019 kms iso link
Once you have obtained the ISO via the legitimate , follow these steps. For testing or if you lack immediate access