PDF is a print format first. Some PDFs contain selectable Chinese text. Others are photographs of pages. Conversion can only change characters that exist as text in the file.
ChineseDocConverter accepts PDF uploads and extracts text for OpenCC conversion, then produces a converted file for download. A text-based PDF is a reasonable candidate. A scan of a book page is not a character conversion problem until someone has turned the image into text.
Text PDFs vs scans
If you can highlight a sentence and copy it, the PDF likely has text. If you cannot, you need OCR first. This site does not advertise itself as an OCR engine.
Fonts
Even when text exists, a PDF may embed a font that only covers Simplified or only Traditional glyphs. After conversion you may need a font that contains the other set. That is covered in Chinese fonts and Unicode.
Practical workflow
- Confirm the PDF has copyable Chinese.
- Upload it to the document converter.
- Choose Simplified to Traditional or Traditional to Simplified, including regional options.
- Check the first page and any headings.
For editable office files, Word or Excel conversion is usually easier to review than PDF.