Three tools sound similar but do very different jobs. A password locks the whole file, a watermark marks it as yours, and redaction permanently erases secret text inside it.
- Use a password when only certain people should open the file at all.
- Use a watermark to claim ownership while still letting people read it.
- Use redaction to wipe out sensitive lines before sharing widely.
- All three are free, run in your browser, and delete your file afterward.
Lock it, mark it, or wipe it, just pick the right one.
Why people mix these three up
"Protecting" a PDF can mean a lot of things, so folks often grab the wrong tool. Someone adds a watermark thinking it hides a phone number, when the number is still right there to copy. The trick is to match the tool to the actual goal. Let us walk through each one in plain terms.
Password: control who can open the file
A password is a locked door for the entire document. Until someone types the code, they see nothing. This is the right choice for contracts, invoices, and anything you only want specific people to read. Add one with our free Protect PDF tool and the file asks for the password every time it opens.
Keep in mind a password is all-or-nothing. It does not blur out one secret line, it guards the whole file. If you later need to share that file with the public, you would remove the lock using Unlock PDF first.
Watermark: say "this belongs to me"
A watermark is a stamp printed across your pages, like "DRAFT" or your company name. It does not lock anything. People can still read every word, which is exactly the point. You want them to see the content, you just want your claim visible too.
Use Add Watermark for sample work, proposals, photos, and previews you send to clients. It discourages copying and reminds everyone whose work it is, without slamming a door in anyone's face. Pair it with a password from Protect PDF when you want both ownership and access control on the same file.
Redact: erase secrets for good
Redaction is the heavy-duty one. It does not hide text, it deletes it. When you black out a Social Security number or a salary figure with Redact PDF, that text is truly gone, not just covered. Anyone who opens the file, even a curious tech person, cannot recover it.
This matters because a common mistake is drawing a black box on top of words with an editor. The box looks solid, but the text underneath is still selectable. Real redaction removes the data, which is why you want a tool built for exactly that.
A quick way to choose
- Only some people should open it, lock it with a password.
- Everyone can read it, but it is yours, add a watermark.
- A few lines must vanish before sharing, redact them.
- Need two of these? Stack them. Redact first, then protect.
Other tools that often join the job
Protection rarely happens alone. Before locking a file you might drop unneeded pages with Delete PDF Pages, or pull out just the relevant pages using Extract Pages from PDF. If you are gathering several documents into one, Merge PDF first, then apply your protection to the finished file so nothing slips through.
Picking the right shield for your PDF
Protecting a PDF is less about one magic button and more about the question you are answering. Who should open it, who owns it, and what must never be seen? Lock it with Protect PDF, mark it with a watermark, or wipe it with redaction, and you will reach for the right one every time. Each is free, runs in any browser with a 50 MB limit, and deletes your upload when it is done.
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