What is a Shortcut??
Any object used in more than one folder should be a shortcut.
A Shortcut is a pointer to where the “real” object resides. In terms of object orientation, it is the first level of inheritance. Source tables, target tables, transformations, and mappings are all objects that may leverage shortcuts. Once a shortcut is established, changes are allowed only to the object in its original location. The locations of the shortcut are read-only.In order to create a shortcut Source folder must be shared folder and destination folder must be opened, otherwise it creates a copy instead of shortcut. Read more Advantages of Shortcuts in Informatica