Go to the official Windows Server 2012 R2 download page.
(Hyper-V or VirtualBox)? How to convert an evaluation to a full version ? Windows Server 2012 R2 | Microsoft Evaluation Center Download W2012R2 Server ISO
Save the ISO file, which is typically around 3-4 GB. Crucial Technical Requirements & Notes Go to the official Windows Server 2012 R2 download page
You will need to sign in with a Microsoft account and fill out registration details. 512 MB RAM
Minimum requirements include a 1.4 GHz 64-bit CPU, 512 MB RAM, and 32 GB disk space, though for production, at least 2 GB RAM and 50 GB disk space are recommended.
Evaluation editions will expire in 180 days. You must activate them during this time, or they will start shutting down.