A friend of mine was selling his car. The buyer asked for a copy of the registration document. Fair enough. But the registration had his home address, his CNIC number, and his father’s name on it. He didn’t want a stranger having all that information.
He asked me: “Can I just cover the personal stuff with a black box before I send it?”
Yes. It takes about 15 seconds. And you don’t need Photoshop, a printer, or a black marker.
If you’ve ever needed to hide sensitive information in a PDF — personal details, financial figures, confidential clauses, phone numbers, email addresses — here’s how to black it out permanently before sharing.
Why you’d need to black out text in a PDF
You’re sharing a document with someone who doesn’t need to see everything on it. Happens all the time.
Sending a bank statement to a landlord for proof of income? They don’t need to see every transaction. Black out the ones that aren’t relevant.
Sharing a contract with a new partner? Certain clauses from the previous version might be confidential. Black them out before sending the draft.
Submitting ID documents online? You might want to hide your CNIC number or date of birth on certain copies. Not everyone needs your full personal details.
Forwarding an email thread as a PDF? Some messages in the thread might be between you and someone else — not meant for the person you’re forwarding to. Black out those parts.
Publishing a document publicly? Government agencies, law firms, and companies do this constantly. They release documents with sensitive parts blacked out. It’s called redaction — and it’s a standard practice, not something shady.
How to black out text in a PDF
Open convertkr.com/redact-pdf. Upload the PDF. The tool opens your document in an editor with a redaction tool selected. Draw a rectangle over the text you want to hide. A solid black box covers it. Repeat for any other areas. Download the redacted PDF.
That’s it. My friend blacked out his address, his CNIC, and his father’s name on the car registration. Sent the clean version to the buyer. Took less time than writing this paragraph.
Covering it up vs. actually removing it
This is important. There’s a difference between hiding text and removing it.
Some people open a PDF in a basic editor, draw a black rectangle over the text, and think they’ve hidden it. They haven’t. The text is still in the file — it’s just sitting behind a black shape. Anyone who selects the area, copies the text, or opens the file in a different viewer can see what’s underneath.
That’s not redaction. That’s a cover-up. And for sensitive information — financial data, personal IDs, legal clauses — a cover-up isn’t good enough.
Proper redaction removes the text from the PDF entirely. The black box isn’t just drawn on top — the content underneath is deleted from the file. If someone inspects the PDF structure, the redacted text is gone. Not hidden. Gone.
When you’re blacking out something that actually matters, make sure your tool does proper redaction, not just visual covering.
What people commonly black out
Personal identification numbers. CNIC numbers, Social Security numbers, passport numbers, driving license numbers. Any time you’re sharing a document that contains an ID number with someone who doesn’t need it — black it out. You can leave the name visible but remove the number.
Home addresses. Rental agreements, utility bills, registration documents, bank statements — they all have your address. If you’re sharing these for verification purposes, sometimes the address is relevant and sometimes it’s not. When it’s not, black it out.
Financial figures. Bank statements often get shared for loan applications, visa applications, or rental agreements. The recipient might only need to see your balance or salary deposits. They don’t need to see every coffee shop transaction. Black out the irrelevant rows.
Phone numbers and email addresses. You’re sharing a document that has contact details of people who didn’t agree to have their information forwarded. Black out their numbers and emails before sending.
Confidential clauses in contracts. You’re sharing a contract template or a reference document with a third party. Some clauses are specific to the original deal and shouldn’t be visible. Black them out.
Children’s information. School documents, medical records, any paperwork that has a child’s details. If you’re sharing these with an institution that only needs partial information, redact the rest.
Salary and compensation details. Offer letters, pay slips, tax returns. You might need to prove employment but not reveal the exact amount. Black out the numbers.
Medical information. Sharing medical reports with insurance but want to hide certain diagnoses or test results that aren’t relevant to the claim. Redact the parts that aren’t needed.
The permanent marker method (and why it doesn’t work)
Some people still print the document, take a black marker, scribble over the text, and scan it back. I’ve seen this more times than I’d like to admit.
Problems with this approach:
It’s slow. Print, mark, scan — three steps that take 10-15 minutes versus 15 seconds online.
The marker might not be opaque enough. Hold the paper up to a light and you can sometimes read through the marker ink. Especially with regular markers — you need a proper permanent marker with thick ink to fully block text.
Scanning introduces quality loss. The scanned version is lower quality than the original PDF. Text is slightly blurry. The document looks unprofessional.
You lose the digital text. The original PDF had selectable, searchable text. The scanned version is just an image. If someone needs to copy any text from the unredacted parts, they can’t.
And you need a printer and scanner. Which half the people reading this don’t have at home.
Multiple areas on one page
You rarely need to black out just one thing. A bank statement might need 15 transactions hidden. A contract might have 3 different clauses to redact. An ID document might have the number, address, and date of birth all needing coverage.
Draw multiple rectangles on the same page. Each one creates a separate black box. You can see all your redactions before downloading, adjust any that are too big or too small, and remove ones you placed by mistake.
Multiple pages
If you’re redacting a 10-page bank statement, you probably need to black out the same types of information on every page — account number in the header, certain transactions in the body.
Navigate through each page, draw your rectangles, and the tool saves all redactions across all pages. When you download, every page has its redactions applied.
It takes a few minutes for a long document. But it’s still faster than printing 10 pages, marking them, and scanning them back.
Can they undo the redaction?
No. Once you download the redacted PDF, the black boxes are permanent. The text underneath is removed from the file. There’s no “undo” on the recipient’s end. They can’t select behind the black box. They can’t extract the hidden text. It’s gone.
This is the whole point of proper redaction versus just drawing a shape on top. With proper redaction, the original content is deleted from the PDF structure — not just visually hidden.
Keep your original unredacted file as a backup. Once you download the redacted version, that version is permanently changed.
Legal and professional use
Redaction isn’t just for personal privacy. It’s a standard professional practice.
Law firms redact client information from documents shared during discovery. Opposing counsel gets the document but certain privileged details are blacked out.
Government agencies redact classified information before releasing documents to the public under freedom of information requests.
HR departments redact salary information from documents shared between departments. The finance team sees the full version. Other departments see the redacted version.
Healthcare providers redact patient information when sharing records for research or auditing purposes. Only the relevant medical data is visible.
Real estate agents redact financial details from documents shared between buyers and sellers. The buyer might see the property details but not the seller’s mortgage information.
If any of these apply to you, proper redaction isn’t optional — it might be legally required.
The privacy thing
You’re blacking out sensitive information because you care about privacy. It would be ironic if the tool you use to do this uploaded your document to someone else’s server.
ConvertKr processes everything in your browser. The PDF doesn’t leave your device. The redaction happens locally using JavaScript. When you close the tab, nothing remains on any server — because it was never on a server to begin with.
For documents containing personal IDs, financial records, or legal information, browser-based processing is the only approach that makes sense.
FAQ
Can the recipient remove the black boxes?
No. The redacted PDF has the text permanently removed. The black box isn’t a layer on top — the content underneath is deleted from the file.
Can I choose a color other than black?
The standard for redaction is black — it clearly signals that information was intentionally removed. If you want to erase content with a white fill instead (so it looks like the content was never there), use the erase tool instead.
Will the rest of the document look the same?
Yes. Only the areas you draw rectangles over are affected. Everything else — text, images, formatting, page layout — stays identical.
Can I redact images too, not just text?
Yes. The black box covers whatever is in the rectangle — text, images, signatures, logos, anything. If there’s a photo you want to hide, draw a rectangle over it.
Does this work on scanned PDFs?
Yes. Scanned PDFs are images, so the black box covers the relevant area of the image. The result is the same — a black rectangle where the sensitive information was.
Is this legally valid redaction?
For most business and personal purposes, yes. The content is permanently removed from the file. For formal legal proceedings, check with your legal counsel about specific jurisdiction requirements.
What if I make a mistake?
Before downloading, you can remove any redaction box you’ve placed. After downloading, the redaction is permanent — which is why you should always keep the original file.
Can I redact a password-protected PDF?
You’ll need to unlock the PDF first, then redact the unlocked version.
Need to hide sensitive information in a PDF? Black it out here — upload, draw over what you want hidden, download a permanently redacted copy. No printing, no scanning, no Photoshop.