A .prn file is a binary file that contains all of the formatting codes necessary for the document to print properly. The Windows print-to-file feature allows you to send a document to a file for future printing. When the print-to-file option is selected, you are prompted to enter a location and file name, and the file is saved with the .prn extension. This can be handy when the printer is offline or temporarily unavailable. Printing a .prn file requires the use of the command-line window.
Open a command-line window. Press and hold the "Windows" key, press and release the "R" key. Release the "Windows" key.
Type "cmd", without the quotation marks, in the "Run" window's text box.
Type "Copy FileName.prn /b prn" and press the "Enter" key. The "/b" switch tells the operating system to output the file in a raw binary format that allows the printer codes to be interpreted correctly by the printer.