Layout change when saved?

I am creating a text editor, as part of my learning process.

I know how to get my text area to save as a pdf, but when the pdf is opened in order to print, I do not want the layout to change.
I would also like to be able to save as an RTF, but have the same problem.

Is there any way of achieving this, or would the layout stay the same automatically?
Could anyone advise me (in NOVICE terms) :slight_smile:

Thank you all in advance.