When you password protect a PDF, anyone who gets the file has to type the password before they can see a single page. That matters for files that shouldn't open for whoever happens to receive them, like a payslip forwarded to the wrong colleague or a contract attached to an email thread with too many people on it.
This tool locks the PDF with AES-256 encryption. The password you choose is the only way in, so the person you send it to needs it too, and you will need it yourself later.
How to password protect a PDF
- Add your PDF. On a computer you can drag it onto the page; on a phone, tap "Select files".
- Type a password of at least 4 characters.
- Type the same password again in "Repeat password" so a typo doesn't lock you out.
- Start the tool and download the locked PDF.
Open the downloaded file once before you send it. Your PDF reader should ask for the password, which tells you the lock worked.
Choosing a password you won't lose
This part matters more than any setting. If you forget the password, nobody can recover it, and that includes us. We don't keep a copy and there is no reset link, because the file itself holds the lock.
A few habits help:
- Use something longer than the 4-character minimum. A short phrase is easier to remember than a random string and harder to guess than a birthday.
- Write it in a password manager or somewhere safe before you close the page.
- Keep an unlocked copy of the original in a safe place if you'll need to edit the document later.
Sharing the password with the reader
Don't put the password in the same email as the attachment. If that email goes to the wrong person, they get both. Send the password a different way: a text message, a phone call, or a WhatsApp message if the PDF went by email.
Where a locked PDF helps
Human resources teams lock payslips, tax forms and employment letters before emailing them to staff. Accountants and small businesses send invoices and financial statements with a password so a misdirected email doesn't expose a client's numbers.
At home the uses are just as ordinary. You might keep scanned copies of your passport, birth certificate or bank statements in cloud storage and want an extra barrier on them. Students sometimes lock a finished thesis or project before sending it to a printer or a friend for review. Schools can protect exam papers or report cards while they are being passed between staff.
Job applicants sometimes do the same with transcripts or ID scans they send by email. If you plan to upload the file to an application portal instead, ask first whether a locked file is acceptable, because the people reviewing it will need the password to read it.
Because the lock lives in the PDF, it stays with the file wherever it goes: an email attachment, a USB stick, a shared drive.
What protection does and doesn't cover
The password stops people from opening the file without it. Once someone types the correct password, they can read the document like any other PDF, so only share the password with people you trust with the contents.
If you want the PDF to show who it belongs to even after it's opened, add a visible mark first with Add watermark, then lock the watermarked copy. Large scanned files can be shrunk with Compress PDF before you protect them. Do any merging first too, because Merge PDF needs password-protected files unlocked.
When you need to remove the password later, for example to merge the file with others, use Unlock PDF with the password you set.
Privacy
Your PDF is processed on our server to add the password, then deleted as soon as the protected file is sent back to you. We don't store the file, and we don't store the password you typed. Nothing is shared, and no watermark or Xon File branding is added to your document.
The tool works in the browser on Android, iPhone, Windows, Mac, Linux and Chromebook, with nothing to install. The upload limit is 100 MB.
Frequently asked questions
Is it free to password protect a PDF?
Yes. Locking a PDF with a password costs nothing, and you don't need an account or sign-up. Upload, set the password, download.
What happens if I forget the password?
The file stays locked. Nobody can recover the password, including Xon File, because we never keep it. Save the password somewhere safe, and keep an unlocked original if you might need it.
How long should my password be?
The minimum is 4 characters, but a longer one is much harder to guess. A short sentence or a few unrelated words that you can remember is a good choice.
Can I lock a PDF on my phone?
Yes. Open the page in your phone's browser, tap "Select files", choose the PDF and type your password twice. The locked file downloads to your phone like any other download.
Will the recipient need special software to open it?
No. A password-protected PDF opens in normal PDF readers on phones and computers. The reader simply asks for the password first.
Can I remove the password later?
Yes, as long as you know it. Upload the file to Unlock PDF, type the current password, and you get a copy without the lock.
Does protecting a PDF change how it looks?
No. The pages, text and images stay the same. The only difference is that the file asks for a password before it opens.