If you don't already have an a subscription account you need your serial number to create one.
"Autodesk® Subscription helps customers maximize the power of their design tools, providing access to the latest software releases, Autodesk® 360 cloud benefits, technical support, and flexible licensing rights."
Once that's done you can access the wide selection of "product enhancement" tools available including:
- Workshare Monitoring
- Revit Server
- E-transmit for Revit
- Revit DB Link
- Revit Extensions....and many more.
You can also log into your Autodesk 360 account via your Autodesk Software (Revit, AutoCAD, etc). It's the log in on the top right corner.