A file is a collection of data stored in one unit, identified by a filename. It can be a document, picture, audio or video stream, data library, application, or other collection of data. The following is a brief description of each file type.
Documents include text files, such as a Word documents, RTF (Rich Text Format) documents, PDFs, Web pages, and others. Pictures include JPEGs, GIFs, BMPs, and layered image files, such as Photoshop documents (PSDs). Audio files include MP3s, AACs, WAVs, AIFs, and several others. Video files can be encoded in MPEG, MOV, WMV, or DV formats, just to name a few.
A library file is a unit of data that is referenced by a specific program or the operating system itself. These include plug-ins, components, scripts, and many others. An application is a program, or executable file. Programs such as Microsoft Internet Explorer and Apple iTunes are both applications, but are also files.
Files can be opened, saved, deleted, and moved to different folders. They can also be transferred across network connections or downloaded from the Internet. A file's type can be determined by viewing the file's icon or by reading the file extension. If the file type is associated with a specific application, double-clicking the file will typically open the file within the program.