Hi! In terms of CAD tools (products), Inventor and AutoCAD are two different products, requiring separate installs. There are quite a few workflows allowing the two tools to interoperate during the design process.
For example, in Inventor you can import dwg files from or export dwg files to AutoCAD. AutoCAD can open the dwg files saved in Inventor. Also, it can create associative drawing views to Inventor components.
Some Inventor users don't use AutoCAD. But, quite a few build up workflows between the two tools to get the job done. It is up to you. There is no one-size-fit-all answer here. It largely depends one what you are trying to do.
Please elaborate exactly you want to do. And, the forum experts can help you find the best workflows to achieve the goal.
Many thanks!
Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer