Your question is Prevent Duplicate Submissions. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
What would you do to ensure this request could not be submitted a second time? Explain how you would clarify the requirement, choose an implementation approach, coordinate with engineering and testing, and validate the behavior under retries, refreshes, and concurrent attempts. Include the acceptance criteria, rollout checks, and monitoring you would require before considering the work complete.