# How to provide pdf_tex files for MWEs?

In my minimal working example I use a pdf_tex file as input. I have been asked to upload it; however, I can only upload the pdf file since pdf_tex is a text file.

Of course, I can paste the content of the pdf_tex file into my question. But what is the preferred course of action here?

I think you should paste the contents of the pdf_tex file into your question. Then all the necessary info will be in the question itself, which is better than relying on external sites, in my opinion.
Please add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}.