Question: how to attach tiff file in autocad?
Answer: In the map of your interest, download the orthomap by clicking the "Download" button at the right of your screen. ... 
Once your file has downloaded, open Autodesk Civil 3D. ... 
At the top left, click on “Connect” on the home folder. ... 
Go to "Add Raster Image or Surface Connection" and enter in a name for the connection.