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Watermarks
Stamp “CONFIDENTIAL”, “DRAFT” or your name across every page, centred or tiled, in any colour and angle.
- ✓ Free
- ✓ No sign-up
- ✓ Private
Watermark, sign and seal your PDFs in seconds.
Protect your documents from copying and tampering. Add a watermark and your signature, then seal the file so anyone can check it hasn’t been changed.
🔒 Your files never leave your device. Everything happens in your browser.
Everything you need to protect a PDF
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Signatures
Draw, type or upload your signature and click to place it. Name, date and document ID are printed underneath.
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Tamper-evident seal
A digital seal is locked to the exact file. If anyone changes even one character, verification fails.
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Scan to verify
A QR code on the page lets anyone check who sealed the document and when, straight from their phone.
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Password lock
Encrypt with AES-256 so only people with the password can open it. You can also block printing or copying.
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Batch & multiple signers
Seal dozens of files at once and download them as a zip. Pass a sealed PDF on and others can add their signature without breaking yours.
More free tools
✍️
Watermark, sign & seal
Protect a document and prove it hasn’t been changed.
Open →🔍
Was this PDF edited?
Look for traces of editing: extra saves, editor apps, mismatched dates and fonts.
Inspect a PDF →🗜️
Compress PDF
Shrink photos and scans to make files small enough to email, without uploading them.
Compress →🧹
Remove hidden info
Strip your name, software, dates, comments and old versions before you share.
Clean a PDF →How it works
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1
Upload
Drop in one PDF or a whole batch. Nothing is uploaded to a server. The files are opened right in your browser.
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2
Customise
Choose a watermark, add your signature, and switch on the seal, QR code or password lock. The preview updates live.
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3
Download & share
Download the sealed PDF. Anyone who receives it can check it’s genuine on the Verify page.
Private by design
Most online PDF tools upload your documents to their servers. qb2pdf doesn’t. Your contracts, invoices and designs are processed entirely on your own device and are never sent to us. You don’t need an account either.
Frequently asked questions
Is qb2pdf really free?
Yes. There’s no sign-up, no watermark of ours on your files, and no limit on how many PDFs you seal.
Are my files uploaded anywhere?
No. Your PDFs are opened, edited and sealed inside your browser. They never leave your computer or phone.
How does someone check my PDF is genuine?
They open the Verify page and choose the file, or scan the QR code on it. qb2pdf shows who sealed it and when, and whether it has been changed since.
Can qb2pdf tell if a PDF was edited with AI?
No tool can reliably tell that, because text and images look the same in a PDF whether a person or an AI produced them. Our PDF inspector shows the real traces editing leaves inside a file, such as extra saves, editing apps and out-of-place fonts, so you know what to ask about.
What is my “signer ID”?
A short code that identifies your personal signing key, which is created in your browser the first time you use qb2pdf. Share it with people you send documents to so they can confirm the seal is really yours. Use Back up key in the app to keep a copy, because clearing your browser data deletes it.
Is this a legally binding e-signature?
A qb2pdf seal proves which signing key sealed a document and that the file hasn’t been altered since. Whether that’s enough for a particular contract depends on where you are and what you’re signing. Some documents need a certified e-signature service or a notary.
Will Adobe Reader show the signature as “certified”?
No. Adobe’s certified signatures require a paid certificate from an approved authority. Your watermark, signature and password lock work in every PDF reader, and the tamper seal is checked on qb2pdf’s Verify page.