You have a document that you update regularly. To access it directly froma/an:

A folder is a container for organizing files and other folders, but it does not provide direct one-click access to a specific document; you still need to open the folder and locate the file.

An icon is a graphical representation, but it is specifically a shortcut icon that provides direct access to a file, not just any icon representing the file itself.

A library in Windows is a virtual collection of folders and files for organization, but it doesn't offer direct one-click access to a specific document like a shortcut does.

A shortcut is a small file that points to another file or program, allowing users to quickly access the target item from a convenient location, such as the desktop or a specific folder, without moving the original file. This is ideal for frequently accessed documents because it provides direct access.