Unsure if this works on every single version of Windows, but this is how I did it: you create the document in Wordpad and save it in .rtf format. The .pdf format is unavailable.

Then close Wordpad, re-open it and go back to the saved file.

If you go to "Save as", this time .pdf format will be added to the list of available formats. You can then save the identical document as a .PDF document.