The .prn file extension is given to Printer Text Files. These files are created when you choose the "Print to File" option from a variety of software applications. These files contain an image of the very same things that would have been printed by your computer had you actually printed the file to an actual printer.
PRN files are similar in nature to PostScript files. Creating a PRN file allows you to print the file from any computer, even if the computer does not have the application that the file was created in. For example, if you had a file that had been created in PowerPoint, you could create a PRN file by choosing the "Print to File" option within the application and then print that file later from a computer even if that computer does not have PowerPoint installed.
Unfortunately we have not received enough suggestions for software that can open PRNFILE files yet.
File.org aims to be the go-to resource for file type- and related software information. We spend countless hours researching various file formats and software that can open, convert, create or otherwise work with those files.
If you have additional information about the PRNFILE file format or software that uses files with the PRNFILE suffix, please do get in touch - we would love hearing from you.