Autodesk Civil 3D 2021 is not available as a permanent "free" download for general commercial use, but you can access it legally through a or a one-year renewable education plan for students and faculty. Official Access Options
You can obtain the software through the following legitimate channels: Autodesk Civil 3D 2021 Free Download
How students can verify educational eligibility for themselves Autodesk Civil 3D 2021 is not available as