If you do not have a license or subscription, (beyond the 30-day trial, which is no longer offered for such an old version).
If you do not have a subscription or a legacy perpetual license, you cannot legally activate AutoCAD 2018. You would need to subscribe to the current version of AutoCAD, which may allow you to install previous versions as a benefit. autocad 2018 download
Before downloading, verify that your computer can run the software efficiently. If you do not have a license or
There are a few ways to download AutoCAD 2018: (beyond the 30-day trial