The situation this actually solves
It's a specific, common bind: you have a PDF and you need to change something in it — fix a typo in a contract clause, update a figure in an old report, or just get a document's wording back into a format you can actually edit. The PDF itself is a dead end for editing. Converting it to a genuine .docx file gets you back into Word, Google Docs, or LibreOffice with the text ready to work on.
This is a rescue operation for the words, not a perfect resurrection of the original file. Knowing that going in sets the right expectation for what comes out.
How the heading detection actually decides what's a heading
Since a converted PDF has no memory of which text was styled as "Heading 1" in whatever program originally created it, the conversion falls back to a simple, honest heuristic: text that's noticeably larger than the surrounding body text gets treated as a heading and rendered bold in the output; everything else becomes regular body paragraphs.
This works well for documents with a clear visual hierarchy — a report with obviously bigger section titles will convert cleanly. It works less well for documents where headings are the same size as body text but distinguished only by color or a different font, since size is the one signal this approach actually has to go on.
What doesn't survive the trip
Tables, columns, images, and precise fonts from the original PDF aren't reconstructed — this is a text-and-basic-headings conversion, not a full document-layout rebuild. A two-column newsletter or a document full of tables will come back as plain, single-column paragraphs, which may or may not be usable depending on what you actually need from it.
If a table of data specifically is what you're after, PDF to CSV or PDF to Excel exist precisely because they reconstruct row-and-column structure, which a general text conversion doesn't attempt.
When to reach for this, and when not to
This is the right call when the actual goal is editable text — you need to change wording, and a plain reflow of the content into Word is genuinely all you need. It's the wrong call when visual fidelity to the original PDF's exact layout matters more than editability; in that case, you're better off treating the PDF as the final format and making any changes through a PDF editor instead of round-tripping through Word.