Editing example written work for PhD opportunity? For an interview for a PhD, I have been asked to provide 'an example of some written work from a project I have worked on in the past'. I'm assuming this is generally intended to be previous coursework I have completed for my undergraduate degree. Should I send an example of my work as it was when I submitted it for marking, or make changes to it so that it is further improved/more appropriate for the role?
Send the best document you can.  It does not matter if it was marked in the past or not.  It does not matter when you wrote it or when you edited it.
You can ask a faculty member from your previous degree for detailed advice.