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Preparing a PDF Before You Send It: Watermarks, Signatures, and What to Check First
Getting a PDF ready to send is usually the last five minutes before it leaves your hands — and also the point where mistakes are easiest to miss. This is less about which button to click and more about the small checks worth doing before a document goes to a client, a landlord, or your own team.
Marking a document as draft, sample, or confidential
Short answer: Open the Watermark tab, type text like DRAFT, SAMPLE, or CONFIDENTIAL, pick a diagonal or tiled layout, a color and opacity, then apply it across every page before you send the file out.
A watermark is a cheap insurance policy: it tells anyone who receives the document — intentionally or by accident — that it isn't the final version. Say you're sending a proposal to three prospective clients for feedback before locking in pricing; stamping every page with SAMPLE or DRAFT means nobody mistakes an early cut for your final offer, and it's obvious at a glance even if the file gets forwarded past the original recipient.
The layout choice matters more than it seems. A single diagonal watermark across the middle of the page reads as more formal and is less visually noisy for text-heavy documents; a tiled, repeated pattern is harder to crop or clone out of an image and works well if you're sharing a document more widely and want the marking to survive a screenshot of just part of a page.
Signing an agreement before you send it
Short answer: Use the Sign PDF tab to draw your signature or type your name in a handwriting-style font, choose which page and corner to place it on, then click "Add signature to PDF" to stamp it permanently onto the document.
For everyday paperwork — a freelance agreement, a rental application, an internal sign-off sheet — a drawn or typed signature placed directly on the page is often all that's needed. It's worth double-checking placement before you finalize: pick the page that actually needs signing (not always the last one, especially in multi-section contracts), and choose a position that doesn't overlap existing text or a logo.
One distinction worth knowing: this produces a visual signature, not a cryptographically certified digital signature with an audit trail. For most day-to-day agreements between two parties that's perfectly fine; for anything requiring formal certification (some real-estate closings, notarized documents, certain government forms), a dedicated e-signature platform with identity verification is the more appropriate tool.
What this tool doesn't do yet — and reasonable workarounds
Short answer: There's no dedicated crop, redact, or password-protect feature yet. Rotate, watermark-as-cover, and an export/re-import workflow through Images to PDF can substitute in a pinch, but none of them fully replace the real feature.
Being upfront about gaps is more useful than pretending they don't exist. Three requests come up often enough that they're worth addressing directly:
- Cropping a page — trimming a wide margin or a scanned edge isn't built in yet. As a workaround, export the page as an image with PDF to Image, crop it in any image editor, then rebuild the PDF with Images to PDF. It's a few extra steps, but it gets you there today.
- Redacting sensitive text — there's no black-box "cover and remove" redaction feature. A high-opacity watermark block positioned over a sensitive line is a visual stand-in, but — and this matters — it only covers the appearance; the underlying text can still exist in the file's structure, so it is not a substitute for true redaction on anything genuinely sensitive (a Social Security number, an account balance, a legal case detail).
- Password-protecting the file — adding an open password or restricting printing/editing isn't available here yet. If a file needs to be locked down before it leaves your machine, run it through a dedicated PDF-encryption step afterward, or rely on your file-sharing platform's own password option in the meantime.
All three are reasonable additions we're evaluating for a future update — flagging them here so you know exactly what to expect (and what not to rely on) today, rather than discovering the gap partway through a sensitive document.
Illustrative examples only — not a guarantee of exact results for your file
| What you need | Available today | Workaround |
|---|
| Trim a scanned page's border | Not yet | PDF to Image → crop → Images to PDF |
| Hide one line of sensitive text | Not yet (true redaction) | Opaque watermark block as a visual-only cover |
| Lock a file with a password | Not yet | Encrypt separately after editing here |
A quick pre-send checklist
Short answer: Skim every page for stray sensitive content, confirm page order after any merge or reorder, check rotated pages look upright, and open the final downloaded file (not just a thumbnail) to confirm watermarks, page numbers, or a signature landed exactly where you expected.
Most PDF mistakes that reach a recipient are avoidable with about sixty seconds of review. Scroll through the finished file end to end rather than trusting that the operations you ran "probably worked" — a merge that put pages in the wrong order, or a watermark that landed slightly off a text block, is far cheaper to fix before sending than after.
Good to know: Every step described here — watermarking, signing, rotating, and the image export/re-import workaround — runs with the open-source pdf-lib library directly in your browser. Files are never uploaded to a server.
Frequently asked questions
Can I black out or redact sensitive text before sharing a PDF?
Not yet with this tool — there's no visual redaction (black-box cover) feature today. As a workaround, you can add a solid, high-opacity watermark block positioned over the sensitive area using the Watermark tab, though that's a cosmetic cover rather than true redaction, since the original text can still exist underneath in the file's structure. True redaction — permanently removing the underlying text and images, not just covering them visually — is a feature we're evaluating adding in the future.
Can I crop a PDF page to remove margins or a scanned border?
Cropping isn't available yet. Today the closest options are Rotate, to fix a sideways scan, and PDF to Image plus Images to PDF, which lets you export a page as an image, crop it in an image editor, and rebuild a PDF from the cropped image. A dedicated crop tool — trimming a page's visible area directly, without the export/re-import round trip — is on our list of possible additions.
Can I add a password to lock a PDF before sending it?
Not currently. This tool doesn't yet include a 'Protect PDF' option to add an open password or restrict editing/printing. Until that's available, if a document needs to be locked, encrypt it with a dedicated PDF encryption tool after finishing your edits here, or use your operating system's built-in file-sharing password options as an interim step. Adding password protection is one of the features we're considering for a future update.
What should I check on a PDF before I send it to someone else?
Open every page and skim for anything you wouldn't want a stranger to see — account numbers, another person's contact details left over from a template, or comments meant only for internal use. Check that page order is correct after any merging or reordering, confirm rotated pages actually look upright, and if you added a watermark or page numbers, open the final file (not just the preview) to make sure they landed where you expected. It only takes a minute and catches most avoidable mistakes.
How do you add a signature to a PDF before sending it?
Open the 'Sign PDF' tab, upload your file, then draw your signature with a mouse or finger, or type your name and choose a handwriting-style font. Pick the page and a corner or center position, then click 'Add signature to PDF' — the signature is drawn permanently onto that page. This is a visual signature for everyday agreements, not a cryptographically verified digital signature; for documents that require legal certification, use a dedicated e-signature service instead.
Related guides
A note on this guide: This article is provided for general, informational purposes to help you prepare PDFs effectively. It is not legal or security advice regarding redaction, encryption strength, or e-signature validity for your specific situation — for documents with real legal or confidentiality stakes, consult a qualified professional or a purpose-built compliance tool.