How to make a scanned PDF searchable

First, check whether it's already searchable

Open the PDF and press Command-F on a Mac or Ctrl+F on Windows, then search for a word you can see on the page. Or try to drag-select a line. If nothing is found and nothing highlights, the PDF is an image and needs OCR. Many scanner apps add the text already, so check before you convert anything.

Scan it searchable from the start, on iPhone

The easiest searchable PDF is one that never needed fixing. The SignMaster app for iPhone and iPad reads the text of every page on the phone while it builds the PDF, on every plan, including Free.

1. 1

   Scan the pages

   Open the Scan tab and capture the pages with Apple's document camera. Already have photos or JPGs of the pages? Tap Photos or Files and pick them instead.

2. 2

   Save the PDF

   Tap the checkmark, name it and tap Save PDF. You'll see "Reading text on page 1 of 3" and so on while each page is read.

3. 3

   Use the text

   The text sits invisibly behind each page, so you can select and copy it in any PDF reader. Copy text puts everything the scan reads on the clipboard, and the Documents search finds the scan by any word inside it.

Fix a scanned PDF you already have

• Adobe's free online OCR tool. Drop a PDF on Adobe's OCR page and it recognizes the text and creates a searchable PDF. Adobe says it's free, and that you sign in to download the result or get a share link.
• Adobe Acrobat Pro on a computer. Open the scanned PDF, choose the Scan & OCR tool and recognize the text; Acrobat adds the text layer to the file. It needs a paid Acrobat plan, which Adobe offers as a free trial.
• Genius Scan Ultra on iPhone. Its on-device text recognition adds a text layer to your PDFs, and its help center explains how to run it on documents you scanned before. It's part of the $39.99-a-year Ultra plan.
• Preview on a Mac: copying only. Apple's Preview guide describes Live Text for selecting and copying text in an image. It doesn't describe saving a searchable text layer into a scanned PDF, so use one of the tools above when the file itself must be searchable.

Getting accurate text

• Start with a sharp, flat scan. OCR reads what the camera saw; blur, shadows and curled pages turn letters into guesses.
• Light it evenly. A shadow across the bottom third of a page is the most common reason a line comes out as nonsense.
• Mind the language. SignMaster's text recognition is set up for English and Spanish. For other languages, check the tool supports yours.
• Expect printed text to work best. Handwriting, stamps and faint thermal print are hit and miss everywhere.
• Proofread what matters. Search on a dollar amount or a name before you rely on it; a 5 read as an S is a classic.

Why it matters for contracts

A searchable contract lets you jump to the payment clause, copy a job address into an invoice, and find last spring's agreement by the customer's street. Screen readers can read it aloud. It also changes how you hide information: drawing a black box over searchable text can leave the text underneath. SignMaster's redaction rebuilds the page so nothing under the box survives.