How to password-protect a PDF for free, without uploading it
Updated 11 October 2026
Adding a password to a PDF means only the person with the password can open it. You can do it for free in your browser, and your document never leaves your computer or phone.
Tenancy application – Parkside Estates Leeds – 11/10/2026
Why add a password
Emails get forwarded, sent to the wrong person, or sit in an inbox for years. A password means that even if the file ends up in the wrong place, it cannot be opened without the password. Cachety protects your PDF with strong AES-256 encryption, the standard banks use. Most free tools ask you to upload your file first, which rather defeats the purpose. Cachety does everything on your own device instead.
How to do it with Cachety
- 1Open cachety.com in your browser.
- 2Drop your PDF or photo onto the page.
- 3Type a watermark with the purpose, recipient and date, for example: Tenancy application – Parkside Estates Leeds – 11/10/2026.
- 4Check the preview, then turn on the password option. Type your own password or press Generate for a strong one.
- 5Download the protected PDF and send it.
If you copy the generated password, Cachety wipes it from your clipboard after one minute, so it does not linger where other apps might read it. Paste it somewhere safe first.
Send the password a different way
This is the golden rule. If you send the PDF and its password in the same email, anyone who gets hold of that email has both. Send the file by email and the password by text message, or read it out over the phone.
- File by email, password by text message.
- File through an upload portal, password by phone call.
- Never put the password in the email subject or file name.
What about photos?
Images cannot hold a password on their own. If you add a password to a photo, Cachety gives you an encrypted PDF instead, which opens in any normal PDF reader once the password is entered. Sending several documents? Combine them into a single PDF in the order you choose, so the recipient only needs to type one password.
Keep a note of the password. If it is lost, nobody can open the file, not even Cachety, because the password is never sent to us or stored anywhere.
A password protects the file on its way. Once the recipient opens it, they can read it, so the watermark still matters: it tells everyone who the copy was for. Neither can stop someone photographing the screen, but together they make misuse much less likely. If you suspect your details have been misused, contact your bank and report it to Action Fraud.
Frequently asked questions
- Is it really free to password-protect a PDF?
- Yes. Cachety is free, with no account and no tracking. It is open-source software made in France.
- Will the recipient need special software?
- No. Any standard PDF reader, including those built into phones and web browsers, will ask for the password and open the file.
- Can I add a password without a watermark?
- Cachety is designed to watermark first, then optionally add a password. A short watermark with the purpose, recipient and date is a good habit for any sensitive document.
- What makes a strong password?
- Long and random is best. The Generate button creates one for you, so you do not have to think one up.