The "Print to file" command creates a PRN file containing instructions for the printer. A PRN file is not the actual document you are printing, so you can't open it with any standard text display program. When a PRN file opens in a standard text display program, such as NotePad or TextEdit, the text looks like a collection of random symbols. If you have PostScript printer drivers, you can open the PRN file in a PostScript viewer. In order to view a PRN file as readable text without PostScript printer drivers, you will need to change your printer settings.
Go to your Printer settings, and click "Add Printer."
Select the "Generic/Text-only printer" and install it as the new printer.
Print the PRN file to this generic, text-only printer.