It is easy to answer the last question in a long email and miss two earlier ones. Here, AI is more useful as a careful reader than as a mind reader.
Remove names, addresses and other sensitive details. Then paste the text and write:
"First make a checklist of every question, request, date and decision the sender is waiting for. Quote a few words that show where each item appears. Do not invent answers. Then draft a friendly, concise reply in which each item gets an answer or the marker [needs input]."
An email about a meeting, a budget and a delivery might then produce three clear lines: confirm the time, state the spending limit and fill in the delivery date. Review the list, replace the gaps and send only when the tone and facts are right.
You can try this in Gemini, whose free tier with a Google Account is intended for tasks including writing help. Paid plans offer higher usage limits, but are not required for this small test. The same approach works in other common chat assistants. Do not paste confidential work email or personal data into a consumer service.