An INCA file contains page element previews used by InCopy, a word processor that integrates with the Adobe InDesign page layout program. It stores page element previews from a subset of an InDesign document (.INDD file), as well as access permissions for modifying associated .INCX linked content files. INCA files are used to divide the work necessary for editing a publication.

Assignment files are created using InDesign and then assigned to a specific editor, who has permission to edit page content using InCopy. Once the page is complete, the editor notifies the sender. This process is useful in several ways: Dividing up editing tasks between multiple editors. Preventing unwanted changes to protected portions of InDesign documents, such as the master layout. Reducing the file and project size sent to editors. Using a check-in/check-out system so that only one worker has access to the page content at a time. Tracking which editors have modified what portions of a document. INCA files are exported with INCX linked content files, which contain the text, graphics, and frames to be modified. Editors typically access INCA and INCX files over a network. NOTE: INCA files have been replaced by .ICMA files in InDesign and InCopy CS4 and later.