PostScript is a page description language used as a vector graphics format for documents and printers.
Over the years, Post Script has become a standard in the printing industry, but it has been replaced in large part by the Portable Document Format (PDF) which was also developed by Adobe and which inherited many of PostScript’s properties. As a rule, desktop publishing programs tend to include an export function for this printing format.
In practical terms, however, any application (any word processing program, for example) can produce a Post Script code with the help of a printer driver. This code can then either be sent directly to a Post Script-capable output device or written to a file. Individual pages and graphics in this format can also be imported by desktop publishing programs and some other applications in the form of encapsulated PS files.
Applications running on Unix-like operating systems generally send print jobs to the printer server or the local printer system in PostScript, where they are converted to device-specific code, usually with the help of Ghostscript.