What is a lnk file and how do I open a lnk file?

LNK  (also known as shell links) are shortcut files  that allow access to a file from a second location. They assume the characteristics of the files to which they point. The LNK extension is used by Windows as a reference to an original file, similar to an alias on Mac. LNK contains the shortcut target type, location and file, as well as the program that opens the target file and an optional shortcut key. LNK files use the same icon as their target file, with a small curled arrow to indicate that the file points to another location. When double clicked, the LNK file acts exactly the same as its original. File shortcuts were first introduced in Microsoft Windows 95. Microsoft Windows uses .lnk as the file extension for shortcuts to local files, and .URL for shortcuts to remote files, like web pages.
Shortcuts are typically implemented as a small file containing a target URI or GUID to an object, or the name of a target program file that the shortcut represents. The shortcut might additionally specify parameters to be passed to the target program when it is run. Each shortcut can have its own icon. Shortcuts are very commonly placed on a desktop, in an application launcher panel such as the Microsoft Windows Start menu, or in the main menu of a desktop environment. Although shortcuts, when created, point to specific files or folders, it is possible for them to break if the target program is moved to another location. When a shortcut file that points to a nonexistent target is opened, Windows Explorer will attempt to repair the shortcut.