[scribus] How it would be possible to render our PDFs selectable?

[Editor, JOTCSA]

Hello,
I have just discovered that my PDF files I generated with Scribus (1.4.4 
and 1.4.5 versions) are not selectable and copying is not possible. Is 
there a way to do it so that the text can be selected and copied?
Thank you.
Dr. Barbaros Akkurt, PhD
Managing editor, JOTCSA