AutoCAD Mechanical ships with content libraries that contain over a half a million pre-drawn standard parts and features. They comply with a wide range of international drafting standards. Autodesk periodically updates content libraries and makes them available through Autodesk 360. You can sign in to Autodesk 360, check for updates, and update your content libraries, if new updates exist.
You can customize the standard part libraries, create your own content libraries from scratch, or use content libraries created by others.