Current versions are managed via the Autodesk Account, where users simply sign in to activate their software.
Authentic installation of AutoCAD 2013 requires a specific to differentiate between standalone versions and those included in suites: AutoCAD 2013 (Standalone): 001E1 AutoCAD Architecture 2013: 185E1 AutoCAD Civil 3D 2013: 237E1 AutoCAD Design Suite Premium 2013: 768E1 Activation Reality for Legacy Software
While there are numerous guides online discussing the use of "keygens" for AutoCAD 2013, it is critical to understand that this software version is officially by Autodesk. Use of third-party activation tools often violates terms of service and poses significant security risks. Official Installation & Product Keys