Hi
@BobThebIlly this is definitely not a silly question, as law firms often use this kind of somewhat ambiguous terminology on their application forms (particularly in relation to work experience). Unhelpfully, there is no general consensus as to their interpretation, as different recruiters have different views of what terms like "work" and "extracurriculars" refer to and the extent to which they can overlap. For this reason, people often encounter such grey area roles which are not easy to classify.
As for your question, I would personally interpret "voluntary work" as meaning work you were not paid for. To qualify for "work: (rather than extracurriculars or hobbies, which are activities that are also not paid), I think there would be a general expectation for the role to involve substantial recurring tasks and responsibilities other people rely on you for. Applying this to an events manager role in a university society, I believe it would likely be included in a volunteer work category.
Finally, for filling in the fields:
- In the organisation category I would write the name of the university and the society;
- In the role category I would write "Events Manager";
- In the "How did you get the role" category I would provide a brief explanation of the selection process - i.e. were you elected following a campaign, were you selected by another society member after an application process, etc.