The Circulation module keeps track of library materials that are borrowed. It determines when materials are due to be returned, generates reminder notices when they're overdue, and calculates fines if they're returned late or if something is lost and keeps track of financial obligations.

The Cataloging module adds, modifies, and removes records in the library catalog. The library catalog is the database that contains records describing the books and other materials in the library's collection.

The Online Catalog, or Online Public Access Catalog, or OPAC, is the electronic equivalent of a card catalog. It allows library patrons to search the library catalog through a computer, using a wide variety of search options. Because the online catalog is integrated with circulation, it can tell you what books are currently on the shelf, and when books that are checked out are due to be returned. In the Voyager system, the online catalog has a web-based interface.

The Voyager system can also manage acquisitions (ordering and paying for new library materials), serials (keeping track of the receipt of serial publications like newspapers and magazines), and media scheduling (managing reservations for the use of equipment or materials).