When ChatGPT searches, it fires queries against a web index (Bing's index plus OpenAI's own crawl), retrieves candidate pages, and writes an answer that links the sources it used. ChatGPT had already passed 1 billion web searches in a single week by April 2025, per OpenAI's own announcement. To be eligible, your pages must be reachable by OAI-SearchBot, the crawler that feeds search, not GPTBot, which gathers training data.
Most "ChatGPT SEO" advice quietly mixes two jobs: getting cited when ChatGPT answers a question, versus using ChatGPT to draft content. Only the first is what this surface optimizes for.