The application layer is the topmost layer in the OSI model, which is a framework used to understand network communication. It provides the interface for users and applications to interact with the network. This layer enables software applications to send and receive data over the network, ensuring that the information is formatted correctly for the receiving application. Common protocols that operate at the application layer include HTTP for web browsing, SMTP for email, and FTP for file transfers. By managing these protocols, the application layer facilitates communication between different software applications, allowing them to work together seamlessly across networks.