Exif (despite being an acronynm it is usually written as "Exif" rather than "EXIF") is a file format developed by the Japan Electronic Industry Development Association (JEIDA) principally for use by digital cameras. The specification uses the JPEG, TIFF and RIFF formats, with the addition of metadata tags.
EXF file suffix is associated with CostX. File is used to data exchange.
EXF file suffix is associated with ExactFile. Checksum digest file.