Will this give me the expandable FAQ box in Google?
Almost certainly not. In August 2023 Google narrowed FAQ rich results to well-known, authoritative government and health websites, and removed them for everyone else. If you added FAQPage markup and the accordion never appeared, that is why, and no amount of correcting the markup will bring it back. The change was part of a broader effort to reduce clutter in the results page, and it also affected HowTo rich results.
Then why add FAQ schema at all?
Because search results are no longer the only consumer of it. AI answer engines, assistants, and the generative summaries at the top of search results all parse structured data to find quotable, attributable answers, and a clean question-and-answer pair is the easiest thing in the world for them to lift and cite. The rich result was the old payoff. Being extractable by the systems that now sit between a searcher and your page is the current one.
Do the questions have to appear on the page?
Yes. Google's guidelines require the marked-up content to be visible to a user who visits the page, and an FAQPage whose questions exist only in the JSON-LD is a violation that can attract a manual action. The text does not have to be byte-identical, but it must be substantively the same content. If you find yourself writing questions in the markup that you would not want a reader to see, that is the signal to stop.
How do I add a long, multi-paragraph answer?
You cannot do it in the input here, because the format is one question and answer per line with a pipe between them, and a line break ends the entry. Generate the structure with a short version of the answer, then paste the JSON into an editor and replace the answer text with the full version. Remember that JSON strings need their line breaks escaped, so paragraphs become \n sequences rather than real newlines.
Is my content sent anywhere?
No. The JSON-LD is built in your browser from what you type, so unpublished FAQ content stays on your machine.