"Could you send that over?" leaves the timing open. You may mean this afternoon while the recipient assumes next week.
State what you need and when you need it. Give the reason for the timing if it helps the person understand the request. For example, a draft needed before a meeting has a different deadline from background material you want to read eventually.
Leave room for an answer
Ask whether the date is workable when you are making a request rather than issuing an agreed requirement. If it is not, discuss what can be provided by then or when the complete answer will be available.
Confirm the arrangement if it affects other people's plans. Avoid using "as soon as possible" when there is a real date you can name. If the deadline changes, tell the recipient promptly. A clear date allows someone to assess the task against their commitments instead of trying to infer urgency from the number of follow-up messages you send.
