The links that used to host the 2012 trial (often found on old forum posts or third-party sites) have mostly been depreciated or removed by Autodesk.
If you do not see the 2012 option, it is possible that your license type (usually newer subscription-only models) does not grant access to versions that old, or the serial number you possess is not linked to that specific version year. autodesk autocad 2012 download trial
Before attempting an installation, ensure your hardware matches the legacy requirements for AutoCAD 2012 How to download available previous versions - Autodesk The links that used to host the 2012
However, you can still find relevant content and alternative ways to access or install the software if you have existing credentials: Official Trials and Alternatives autodesk autocad 2012 download trial