Scanned PDF? How to get selectable, searchable text (OCR)

Updated 13 October 2026 · ChatPDF guides · 10 sources

AI can miss or misstate things. Summaries and answers from AI tools, ChatPDF included, can leave out important details or get them wrong. Check anything that matters against the document itself, especially legal, medical, financial and exam material.

Key points
  • A scanned PDF is a picture of each page. Without a text layer you cannot select, search or copy the words, and text-based tools cannot read it.
  • OCR (optical character recognition) estimates the text in the picture and can add it as an invisible layer. It makes mistakes, so check names and numbers. 1
  • On iPhone, Live Text copies text from the camera or an image, Notes can insert scanned text, and on iOS 27 Preview can embed OCR text when exporting a PDF. 2,3,4
  • On a computer, the open-source OCRmyPDF tool adds a text layer using the Tesseract engine; it does not read handwriting. 1,5

If you cannot highlight a single word in a PDF, it was almost certainly made by scanning or photographing paper. The file holds an image of each page, not the characters themselves. To search it, copy from it or use it with tools that read text, you need OCR, which turns the picture of the words into actual text.

Text-based PDF Scanned PDF Text layer: real characters What you see on the page Select, copy and search work. AI PDF tools can read it. No text layer Photo of the page Nothing to select or search; text-only tools see a blank. OCR adds an estimated, invisible text layer on top of the photo. It can contain recognition errors, so check names and numbers.
Why some PDFs have selectable text and others do not: a scan is only a picture until OCR adds a text layer.

How to tell whether a PDF has a text layer

  1. Open the PDF in Preview and touch and hold a word. If grab points appear and you can tap Copy, the page has text 6.
  2. Use Preview's search for a word you can see on the page. If it finds nothing, the visible words are probably only an image 7.
  3. Check several pages. Some PDFs mix typed pages with scanned ones, such as a contract with a scanned signature page at the end.

Option 1: copy just the text you need with Live Text

When you only need a paragraph or a phone number, Live Text is the fastest route. Point the Camera at the paper, wait for the yellow frame around the text, tap the Live Text button, then touch and hold to select text and tap Copy, Translate or Share 2. Live Text also works on images in Preview: open an image that shows text, select it and tap Copy 8.

That second route works for a scanned PDF too. In Preview, export the page as a PNG or JPEG with Export 4, open the image and copy the text from it. Live Text is not available in every region or language 2.

Option 2: capture the text directly in Notes

If you still have the paper, Notes can turn it into text straight away. In a note, tap the Attachment button, tap Scan Text, frame the text, adjust the selection and tap Insert 3. You get editable text in the note rather than a picture, which you can then copy, search or turn into study notes. Notes search also finds text in documents you scanned into notes 9.

Option 3: add a text layer on iPhone with Preview (iOS 27)

Apple's iOS 27 guide lists an Embed Text option when you export a PDF from Preview, which runs OCR on images and makes the PDF searchable 4:

  1. Open the scanned PDF in Preview.
  2. Tap the arrow next to the file name, then tap Export.
  3. Choose PDF as the format and turn on Embed Text.
  4. Choose a location, rename the file if you like, and tap Save.

Then open the new copy and test that you can select a word. The iOS 26 version of the export screen does not list this option, so you may not see it on older software.

Option 4: OCR on a computer with open-source tools

OCRmyPDF is a free, open-source command-line program that "adds text layers to images in PDFs," making scanned PDFs searchable. It uses Tesseract, an open-source OCR engine released under the Apache 2.0 license with trained models for more than 100 languages 1,5. It suits people who are comfortable installing software and running a command, and it can process many files at once. Its documentation is candid about limits 1:

Many scanners and copier apps also offer OCR as an option when saving to PDF, so check the settings on the device that made the scan.

Check OCR text before relying on it

OCR guesses each character, and the guesses are not perfect. Typical errors are 0 and O, 1 and l, missing decimal points, broken words at line ends and columns read in the wrong order. Even text-based PDFs can come out with jumbled reading order when tools extract their text, as a benchmark of PDF extraction tools found 10. Before you quote a figure, sign something or feed the text to an AI tool, compare the important lines against the page image. Better scans give better OCR, so see how to scan documents on iPhone for tips.

Where ChatPDF fits

Scanned and image-only PDFs need OCR, which ChatPDF does not have. The app reads the existing text layer, and if there is none it refuses the PDF with a message that it has no selectable text. After you add a text layer with one of the options above, you can import the new copy from Files and ask questions about it. Keep in mind that answers are only as good as the OCR text underneath; see which PDFs work with ChatPDF and how far to trust AI summaries.

Common questions

Can OCR read handwriting?

Not reliably. OCRmyPDF states that it cannot recognize handwriting, and handwritten forms are hard for most OCR. Type out short handwritten passages yourself. 1

Does scanning in Notes make the PDF selectable?

Apple says Notes search finds text in scanned documents, but it does not say the saved PDF gets a selectable text layer. Test by selecting a word in the file. 9,3

Why does my OCR text have strange characters?

Low contrast, blur, curved pages or the wrong language setting cause misreadings. Rescan flat in good light and set the correct language. 1

Sources and further reading

  1. OCRmyPDF documentation. Introduction. ocrmypdf.readthedocs.io
  2. Apple Support. Use Live Text with your iPhone camera (iPhone User Guide). support.apple.com
  3. Apple Support. Scan text and documents in Notes using the iPhone camera (iPhone User Guide). support.apple.com
  4. Apple Support. Export or compress PDFs and images in Preview on iPhone (iPhone User Guide, iOS 27). support.apple.com
  5. Tesseract OCR. Tesseract User Manual (tessdoc). tesseract-ocr.github.io
  6. Apple Support. Annotate a PDF or image in Preview on iPhone (iPhone User Guide). support.apple.com
  7. Apple Support. Open and view PDFs and images in Preview on iPhone (iPhone User Guide). support.apple.com
  8. Apple Support. Interact with text in an image in Preview on iPhone (iPhone User Guide). support.apple.com
  9. Apple Support. Search through your notes on iPhone (iPhone User Guide). support.apple.com
  10. Bast H, Korzen C (2017). A benchmark and evaluation for text extraction from PDF. ACM/IEEE Joint Conference on Digital Libraries (JCDL) 2017. doi:10.1109/JCDL.2017.7991564 ad-publications.cs.uni-freiburg.de
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