I don’t think the marker will care very much. It depends a bit on the question. If you are asked to prepare a briefing note explaining how you would approach a problem then it might make sense to say “I will ensure…”.
If it is more about the overall conduct of an audit, then it is possible to shift to the third person like “It is vital that the audit team…”, or the passive voice like “Invoices must be carefully scrutinised…”