Good evening, @desantij ...
Could you please provide some more detail on your question? I'm not sure what you mean by "download student file...to discussions". Downloading typically involves clicking on a file on a webpage (or in this case, an existing link in a Canvas course). That file might be a PDF, a Word document, or a PowerPoint file that is then saved to your computer. You indicate you want to download "to discussions", but this is where I'm not as clear. Are you wanting to upload (the process of taking a file from your computer and adding it to Canvas) a PDF file and/or a JPG image to a discussion in your Canvas course?
It would also be helpful to know if you are an instructor or a student. If you are an instructor, are you wanting to include the file in a discussion prompt for your students to look at and then post a response about? Or, if you are a student, are you wanting to know how to include a PDF file or JPG image as part of your discussion reply.
If you could help fill in these details, that would be great...thanks! Take care, stay safe, and be well.