To make a scanned PDF searchable, run OCR (optical character recognition): the tool reads the text in the page image and adds an invisible, selectable text layer over each page, so the file looks identical but you can now search, select, and copy its text. A browser-based OCR tool does this on your device, so the scan is never uploaded, with no sign-up. OCR adds a text layer — it does not rebuild the scan into editable fonts or tables.
A scanned PDF is really just a picture of a page: you cannot search it, select its text, or copy from it. OCR fixes that by recognising the words and laying invisible, selectable text over the image. Here is how it works, how accurate it is, and what it can and cannot do.
OCR adds a searchable, selectable text layer on top of each page and keeps the original exactly as it looks. It does not convert the scan into editable fonts, reflowable paragraphs, tables, or form fields — the picture stays a picture; you just gain a text layer over it. If you need to change the wording on a scanned page, that is a separate editing step.
Related tools:
Recognition accuracy depends on the scan: clear, straight, high-contrast text works best, while faint, skewed, or handwritten text may be missed. English text is supported; the recognition engine (about 6 MB) downloads to your browser once on first use, then works offline. Because it runs on your device, a long document can take a few seconds per page and is limited by memory rather than an upload.