What Google has said
Google's guidance for its AI features is that the same fundamentals apply: let Google crawl and index the page, make important content available as text, keep the page eligible for snippets, and focus on helpful, people-first content. There is no special markup or file that switches AI Overviews on.
What tends to help
Match the question closely, ideally in a heading, and answer it in the first few sentences beneath. Cover the follow-up questions on the same page or link to them. Use structured data where it accurately describes the page. Keep facts current and dated, and make it clear who wrote the content and why they are credible.
Track it in Google Search Console: AI Overview appearances are counted within normal search performance, so watch impressions and clicks on the questions you are targeting.