Scan to PDF: Sign & Redact is a free document scanner for iPhone and Android that photographs paper, fills and signs forms, and blacks out text so the words leave the exported file instead of hiding under a rectangle. Version 2.0, released on 7 July 2026, added Bates numbering, AES-256 export passwords and PDF/A-2b archiving, all on the device.
Disclosure: AppStoryo is operated by the studio that develops Scan to PDF: Sign & Redact. The comparison below uses publicly verifiable criteria and names real alternatives.
What does Scan to PDF do that the phone camera does not?
The camera gives you a picture of paper lying at an angle. Scan to PDF finds the four corners, corrects the perspective, cleans a faded receipt with contrast filters, and reorders pages before exporting one PDF. Three things a camera roll cannot do: filling and signing a form with a finger, running text recognition, and blacking out what is nobody else's business.
The iOS build is 97.2 MB, needs iOS 15.5 or later, also runs on a Mac with an Apple M1 chip under macOS 12.4, and ships in 44 App Store languages. Install Scan to PDF from the App Store, or Document Scanner PDF from Google Play.
Why is a black rectangle over a bank statement not redaction?
Because in a PDF the rectangle and the text are separate objects stacked on each other, and only one is visible. The characters remain in the file, selectable and copyable. The United States District Court for the Northern District of California lists the methods that do not work, and puts this one near the top of its filing guidance:
Edits made by graphic and "commenting" tools which can black-out, cover over or remove sections of text can still be removed by anyone to reveal the text underneath.
The same page warns that white font hides nothing and that deleted text survives in metadata. The National Security Agency made the identical point in Redacting with Confidence on 13 December 2005: converting a Word document to PDF does not remove all metadata. Twenty-one years later, people still email pay stubs with a black box drawn over the salary.
Does the redaction in Scan to PDF actually delete the text?
Scan to PDF describes its own behaviour as a true blackout baked into the exported PDF, not a removable layer. That claim is the reason the app exists, and one of the few you can test in thirty seconds.
Export a redacted page, open the PDF in any reader, select all, copy, paste into a notes app. If the blacked-out words appear, the redaction was cosmetic; if the region comes back empty, the characters are gone. Check the page as an image too: clearing the text layer while leaving the original photograph underneath solves nothing. Test any scanner this way. Scan to PDF is on the App Store and on Google Play.
What did version 2.0 add for people who file paperwork?
Version 2.0 is where the app becomes a filing tool. Its changelog lists Bates numbering on every page, exhibit labels with an auto-generated cover sheet, a stamp library, an audit-trail page for signed PDFs, signing with your own certificate behind Face ID, AES-256 passwords on exports, PDF/A-2b archival export, offline text recognition, and GDPR export with secure delete.
Two deserve explaining. PDF/A-2b is the archival flavour of PDF, the one the United States National Archives accepts for permanent records; the same court page notes PDF/A files are least likely to be rejected by a system that caps one filed PDF at 50 MB. Secure delete matters because deletion is not erasure — NIST Special Publication 800-88 draws that line.
How private is Scan to PDF next to a cloud scanner?
The App Store privacy section for Scan to PDF reads Data Not Collected. Apple states in its own documentation that these labels are developer-declared and not independently verified, so read it as a commitment rather than an audit. The Play listing shows no advertising and no in-app purchases, and text recognition uses the platform's on-device engine.
The contrast is not opinion, because the big scanners say it themselves. Adobe Scan's listing says scans are automatically saved to Adobe Document Cloud; CamScanner's invites you to upload documents to Dropbox, Google Drive and OneDrive. For a team those are the right features, and the wrong ones when the page is a passport or a payslip.
Which scanner app should you actually use?
Choose Adobe Scan if you already live inside Acrobat
- Its listing says scans are saved to Adobe Document Cloud automatically, reaching your laptop immediately.
- 1,589,094 App Store ratings averaging 4.88 is a track record no new app has.
- The cost is reach: 397.8 MB, iOS 18.0 or later, 19 languages, and a subscription for the stronger features.
Choose Genius Scan if you export to many different places
- Its listing names Box, Dropbox, Evernote, Expensify, Google Drive, OneDrive, FTP and WebDAV as destinations.
- At 99.3 MB it is the leanest large scanner, with 1,361,270 ratings at 4.90.
- Read the plus signs: text extraction and searchable PDF are premium, and Genius Cloud sync is a separate subscription.
Choose CamScanner if you need the widest language coverage
- 57 languages and 1,900,040 ratings at 4.85, with a dedicated ID and passport mode.
- Membership is billed weekly, monthly, quarterly or annually.
- Cloud upload is central to how it works.
Choose Scan to PDF if the document is nobody else's business
- Redaction that removes text rather than covering it, which none of the three above centres its product on.
- No account, no cloud, no advertising, no watermark and no subscription, in a 97.2 MB app.
- Bates numbers, exhibit labels, AES-256 export passwords and PDF/A-2b for paperwork that gets filed rather than merely stored, on iOS 15.5 rather than the iOS 18.0 Adobe Scan now requires.
When is Scan to PDF the wrong app?
When you need the scans on more than one device. There is no sync and no cloud backup — a deliberate choice with a real consequence: lose the phone and the library goes with it. It is also not a PDF editor, and will not rewrite text somebody else produced.
Two more caveats. The app has no App Store ratings and the Play listing shows a download count in the tens, so no crowd is telling you what breaks. And redaction is only as thorough as your selection — an account number repeated in a page-7 footer survives if you marked page 1. Read the whole document, redact, then test. Install Scan to PDF from the App Store or Document Scanner PDF from Google Play.
What else do people ask about Scan to PDF?
Is Scan to PDF free, and is there a subscription?
It is free on both stores, and the listings show no in-app purchases and no advertising. No trial turns into a plan, no export limit unlocks with a payment, no watermark appears — unusual where Adobe Scan, Genius Scan and CamScanner all describe paid layers in their own listings.
Does Scan to PDF work without an internet connection?
Yes. Scanning, perspective correction, filters, signing, redaction, text recognition and export all run on the phone, which is why the App Store privacy section reads Data Not Collected. It behaves identically in aeroplane mode or a courthouse with no signal, and nothing waits to sync.
How do I check that a redaction really removed the text?
Export the redacted PDF, open it in any reader, select all the text, copy it and paste it somewhere readable. Blacked-out words that reappear were never removed. Then view the page as an image, to be sure the original photograph is not underneath. Test on a throwaway document first.
What is PDF/A-2b and when should I use it?
PDF/A is the archival profile of PDF: fonts and colour are embedded so the file renders the same way in twenty years, and anything depending on external resources is disallowed. The 2b level covers visual fidelity. Use it for anything you keep permanently — the National Archives accepts it.
Does Scan to PDF add a watermark to exported files?
No. The listing is explicit that there is no watermark on anything, ever, and no paid tier exists to remove one. This matters more than it sounds: branding stamped across a signed lease is often enough for the other side to send the document back to you unsigned.
Can I sign a PDF somebody emailed me, or only pages I scanned?
The listing describes scanning a page, filling it, signing it with a finger or your own certificate, and exporting. It does not say whether a PDF produced elsewhere can be imported and signed, so treat that as unconfirmed and check inside the app first.
What is Bates numbering and do I need it?
Bates numbering stamps a unique sequential identifier on every page of a document set, so lawyers, auditors and insurers can point at one page unambiguously across thousands. If you have never needed it, you do not. If you are producing exhibits, it separates a set from a pile.
Is an AES-256 password on an exported PDF strong enough?
The cipher is not the weak part; your password is. AES-256 is the strongest encryption the PDF format offers and is not realistically brute-forced, but a six-character word is guessable whatever sits behind it. Use a long passphrase and send it separately from the file.
Which languages can the text recognition read?
The version 2.0 changelog says offline text recognition with an on-device language picker, but does not list them, and the 44 languages shown on the App Store describe the interface rather than the recognition engine. Check the picker inside the app, particularly for non-Latin scripts.
Does Scan to PDF back up my documents anywhere?
No, and that is the trade. The library lives on the phone behind Face ID, nothing is uploaded and no server holds a copy — which is why the privacy label reads Data Not Collected. A lost phone takes the library with it, so export whatever matters, regularly.
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