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Quick answer
To password protect a PDF, open Zappy Protect PDF, add your file, type a password twice and click Protect PDF. The encrypted copy downloads right away, and anyone who opens it has to enter that password first. It is free, needs no account and adds no watermark. Write the password down before you send the file, because nobody can recover it for you.
How to password protect a PDF in 3 steps
This works the same in any browser on Windows, Mac, Chromebook, iPhone and Android, with nothing to install.
Add your PDF
Open Protect PDF and drop your file in, or tap to choose it. Files up to 50MB work.
Type a password twice
Pick a password and type it again to confirm. A long phrase of ordinary words is stronger than a short jumble of symbols, and easier to share with the person who needs it.
Download the locked PDF
Click Protect PDF. The encrypted copy downloads straight away. Open it once to check that it asks for the password.
How to password protect a PDF on a Mac
Preview, which comes with every Mac, can add a password without any extra software:
- Open the PDF in Preview.
- Choose File, then Export.
- Click Permissions and tick Require Password to Open Document.
- Type the password twice, click Apply, then Save.
On older versions of macOS the Export window shows an Encrypt checkbox instead. It does the same job.
How to password protect a PDF from Microsoft Word
If the document starts life in Word on Windows, you can lock it as you save it:
- Choose File, then Save As, and pick PDF as the file type.
- Click Options.
- Tick Encrypt the document with a password and click OK.
- Type the password twice and save.
This option is not in Word for Mac. On a Mac, save the PDF first, then lock it with Preview or Protect PDF.
Can you password protect a PDF in Adobe Reader?
No. The free Adobe Acrobat Reader can open protected PDFs but cannot add a password. That needs Acrobat Pro, the paid version, where the option is under Protect, then Protect Using Password.
If adding a password is all you need, you do not have to pay for Acrobat. A free tool, Preview on a Mac, or Word on Windows all produce a standard encrypted PDF that opens in Adobe Reader and every other PDF reader.
Swipe to compare →
| Zappy Protect PDF | Mac Preview | Word (Windows) | Acrobat Pro | |
|---|---|---|---|---|
| Price | Free | Free (Mac only) | Included with Word | Paid subscription |
| Works on phones | Yes, in any browser | No | No | App |
| Open password | Yes | Yes | Yes | Yes |
| Blocks copying and printing | Yes | Yes | No | Yes |
| Install needed | No | No | Word | Acrobat |
Open password vs permissions password
PDFs support two kinds of protection, and they are not equally strong:
- Open password. The file is encrypted and cannot be read at all without the password. This is the real protection, and it is what this guide sets up.
- Permissions password. Anyone can open the file, but the reader is asked to block printing, copying or editing. These limits rely on the PDF reader respecting them, so they stop casual misuse, not a determined person.
If a document must stay private, always use an open password. Treat print and copy restrictions as a polite request, not a lock.
How strong is PDF password protection?
Modern PDF encryption uses AES, the same standard used for online banking. The weak point is almost never the encryption; it is the password. A short or guessable password can be cracked by trying millions of combinations, while a long one practically cannot.
- Use at least 12 characters. Four unrelated words, such as maple-river-lamp-seven, are strong and easy to type.
- Avoid names, birthdays and anything printed in the document itself.
- Send the password separately from the file, for example by text message when the PDF goes by email.
When to password protect a PDF
- Tax returns and W-2s you are sending to an accountant
- Pay stubs, bank statements and loan paperwork
- Medical records and insurance forms
- Contracts and offer letters before they are signed
- Anything with a Social Security number, date of birth or account number
Once the PDF is locked, many other tools cannot read it. If you also need to merge, compress or sign the file, do that first and add the password last.
Frequently asked questions
How do I password protect a PDF for free?
Open Zappy Protect PDF, add your file, type a password twice and click Protect PDF. The locked copy downloads right away. There is no account and no watermark.
Can I password protect a PDF in Adobe Reader?
No. The free Adobe Acrobat Reader cannot add passwords; that needs the paid Acrobat Pro. A free browser tool, Preview on a Mac or Word on Windows can do it instead.
How do I password protect a PDF on a Mac?
Open it in Preview, choose File, then Export, click Permissions and tick Require Password to Open Document. Enter the password and save.
Can I password protect a PDF on iPhone?
Yes. Open Zappy Protect PDF in Safari, add the file from Files or Mail, type a password and download the locked copy back to Files.
Can I stop people from printing or copying my PDF?
Protect PDF also restricts printing, copying and editing. Most readers respect these limits, but they can be bypassed with special software, so the open password is the part that truly protects the file.
What happens if I forget the password?
The file cannot be opened by anyone. Zappy does not store passwords, so there is nothing to recover. Keep the password somewhere safe before you send the file.
How do I remove the password later?
If you know the password, use Zappy Unlock PDF to save an unlocked copy. It cannot remove a password you do not know.
Is my PDF safe when I upload it?
The connection is encrypted, the file is used only to create your locked copy, and both the file and the password are deleted within an hour.