What is the function of the Application Layer of the OSI model?

The Application Layer provides the operating system with direct access to network services. It serves as the interface between the user and the network by providing services that directly support user applications. Note that a user-based application like Excel does not operate at the application layer. Instead, the application layer provides an interface so that processes such as Excel or Word that are running on the local machine can get access to network services (e.g., retrieving a file from a network server).

IPCs such as RPCs and named pipes are usually shown as functioning at the session layer.