What you can do with a scanned copy depends on how it was created

A scanned document is a photograph of a piece of paper turned into a digital file. If you scanned it as an image (JPG, PNG, or PDF with images), you cannot edit the text directly — you can only mark it up, crop it, or redraw on top of it. If you scanned it as a searchable PDF or used optical character recognition (OCR) software first, the scanner converted the image into actual text that you can select, delete, and rewrite.

The editing path you take depends on what file type you have and what you want to change. A straightforward markup — highlighting, adding notes, drawing boxes — works on any scan. Rewriting sentences or moving paragraphs requires the text to be extractable first. Before you start, open the file and try to click on a word and drag to select it. If the text highlights, you have an editable scan. If nothing happens, you have an image scan and need a different approach.

Key Takeaways

  • Image scans (JPG, PNG, or image PDFs) let you mark up and annotate but not edit text — try selecting text first to know which type you have.
  • Searchable PDFs and OCR-converted files let you edit text directly by selecting and rewriting, though OCR sometimes misreads handwriting or poor scans.
  • Free tools like LibreOffice Draw, Preview on Mac, or Markup in Windows handle annotation; paid tools like Adobe Acrobat Pro add OCR and full editing.
  • OCR accuracy depends on scan quality — dark, straight scans with clear fonts convert better than tilted, faded, or handwritten pages.
  • For privacy, use offline software like LibreOffice or Preview rather than uploading scans to cloud-based OCR services unless the service publishes its data handling.

Marking up an image scan without converting it

If your scan is an image file or an image-based PDF, you can add notes, highlights, boxes, and arrows without converting the text. On Mac, open the file in Preview, click the Markup toolbar (or press Shift+Command+A), and choose from highlighter, pen, text box, or shape tools. On Windows, right-click the PDF and select "Open with Microsoft Edge," then click the Draw tab to access pen, highlighter, and eraser. Both let you save your marked-up version without changing the original.

LibreOffice Draw, which is free and works on Windows, Mac, and Linux, opens image PDFs and lets you add text boxes, shapes, and freehand drawing. Open the file, go to Insert > Text Box or use the drawing toolbar on the left, and place your annotations. This approach is useful when you want to fill in blanks, add comments in margins, or highlight sections without needing to extract and edit the underlying text.

Markup tools do not change the scan itself — they create a layer on top. If you need to actually rewrite sentences or move paragraphs, you need the text to be extractable, which means converting the image to searchable text first.

Converting an image scan to editable text with OCR

Optical character recognition (OCR) reads the image and converts it into selectable, editable text. Adobe Acrobat Pro includes OCR and can convert a scanned PDF in one step: open the file, go to Tools > Enhance Scans, and click Enhance. The software recognizes the text, makes it searchable, and leaves you with a PDF you can edit. Acrobat Pro costs money and requires a subscription, but it handles poor-quality scans better than free alternatives.

Free options exist if you want to avoid subscription costs. LibreOffice can import a scanned PDF and attempt OCR through extensions, though the process is less direct than Acrobat. Tesseract, an open-source OCR engine, works from the command line on Windows, Mac, and Linux — it is free but requires typing commands rather than clicking buttons. Online services like ILovePDF, Smallpdf, or Google Drive's OCR feature work in a browser: upload your scan, let the service convert it, and read the result. The trade-off is that you are sending your document to someone else's server.

OCR accuracy depends on scan quality. A dark, straight scan with clear printed text converts nearly perfectly. A tilted, faded, or handwritten scan will have errors — the software might read a "1" as an "l" or miss words entirely. After conversion, read through and fix mistakes before you rely on the document.

Editing text in a searchable PDF or converted document

Once your scan is converted to searchable text, you can edit it like any other document. In Adobe Acrobat Pro, click Tools > Edit PDF, then click the text you want to change. The text becomes editable and you can select, delete, or rewrite it. In LibreOffice, import the converted PDF as a document (File > Open), and the text appears in the normal editing view where you can select and change anything.

If you converted the scan using an online OCR service, read the result as a Word document or PDF, then open it in your document editor of choice — Microsoft Word, Google Docs, LibreOffice Writer, or any other program you use. The text is now fully editable. Keep in mind that OCR sometimes creates odd line breaks or spacing, especially if the original scan had multiple columns or unusual formatting. A quick read-through before you finalize catches these issues.

For privacy reasons, if you used an online OCR service, delete the uploaded file from that service after you read the result. Most services do not keep files permanently, but checking their privacy policy tells you how long they store uploads and whether they use your documents to train their software.

Choosing between marking up and converting based on what you need

Mark up a scan if you are reviewing it, adding comments, or filling in blanks — you do not need to change the original text. This is faster and does not require OCR. Use this approach for contracts you are signing off on, forms you are completing, or documents you are annotating for someone else to read.

Convert a scan to editable text if you need to rewrite sections, move paragraphs, or extract information into a new document. This takes longer because OCR is not when ready and usually requires fixing errors, but the result is a document you can edit like any other file. Use this for documents you plan to revise, repurpose, or integrate into other work.

If you are scanning documents yourself going forward, scan at high resolution (300 DPI or higher), keep the page straight, and use good lighting. A clean scan converts to text much faster and with fewer errors, which saves you time fixing OCR mistakes later.

Privacy considerations when converting scans

Offline OCR tools like Adobe Acrobat Pro and LibreOffice keep your document on your computer — nothing leaves your device. If privacy is your main concern, these are the safest choice, though Acrobat Pro requires paying for a subscription and LibreOffice's OCR is less reliable than paid alternatives.

Online OCR services like Google Drive, ILovePDF, or Smallpdf upload your scan to their servers to process it. Check the service's privacy policy to learn whether they delete files after conversion, whether they use your documents to train their software, and whether they encrypt files in transit. Google Drive's OCR is built into Google's broader data practices — if you already use Google services, the privacy impact may be the same as other Google activity. Smaller services like ILovePDF publish their policies clearly, and many delete files within hours of processing.

If your scan contains sensitive information — medical records, financial statements, legal documents — use an offline tool or a service that explicitly states it does not retain or use your files for training. Reading the privacy policy takes five minutes and tells you exactly what happens to your document.

Frequently Asked Questions

Can I edit a scanned PDF without OCR?

No, not the text itself. You can mark it up with annotations, highlights, and text boxes, but you cannot select and rewrite the original text. To edit text, the scan must be converted to searchable text first using OCR.

Why does OCR sometimes get words wrong?

OCR reads images pixel by pixel and guesses what letters they represent. Poor scan quality — tilted pages, faded text, unusual fonts, or handwriting — makes guessing harder. A dark, straight, high-resolution scan of printed text converts nearly perfectly. Handwritten or low-quality scans need manual correction afterward.

Is it safe to upload my scan to a free online OCR service?

It depends on the service and what is in your document. Most reputable services delete files within hours and do not use them for training. Read the privacy policy first — it tells you how long files are kept and whether they are used for anything else. For sensitive documents, use offline software instead.

What is the difference between a searchable PDF and an image PDF?

An image PDF is a photograph of a page — you cannot select or edit the text. A searchable PDF has text data underneath the image, so you can search for words and select them. OCR converts an image PDF into a searchable one.

Do I need to buy Adobe Acrobat Pro to convert a scan?

No. LibreOffice is free and can handle basic OCR. Google Drive offers free OCR if you upload your scan there. Acrobat Pro is faster and more accurate, especially with poor-quality scans, but it requires a subscription. Choose based on how many scans you convert and how much accuracy matters.