If you are sharing a PDF containing sensitive information — a payslip, a contract, personal data — adding a password is a straightforward way to ensure only the intended recipient can open it. You do not need Adobe Acrobat to do this. Here are the best free methods for Windows and Mac.
Method 1: Password Protect Using Microsoft Word
If your document was originally created in Word, this is the simplest approach:
- Open your document in Microsoft Word
- Go to File > Save As and choose PDF as the file format
- Before clicking Save, click Options
- Tick the box that says Encrypt the document with a password
- Enter your chosen password and confirm it
- Click OK, then Save
The resulting PDF will require the password to open. Anyone without the password will see a password prompt when they try to view the file.
Method 2: Use a Free Online Tool
For PDFs you have already received (not created from Word), an online tool is the fastest route:
- ILovePDF (ilovepdf.com/protect-pdf) — upload, set a password, download. Free with no account.
- Smallpdf (smallpdf.com/protect-pdf) — same process, free for occasional use.
- PDF2Go — another reliable option with a straightforward interface.
Upload your PDF, enter the password you want to apply, and download the protected file. The process takes under a minute.
Important: Uploading confidential documents to third-party online tools carries a privacy risk. For highly sensitive files, use an offline method.
Method 3: Use Preview on Mac
Mac users can password protect PDFs directly in Preview:
- Open the PDF in Preview
- Go to File > Export as PDF
- Tick the box that says Encrypt
- Enter and confirm your password
- Click Save
The exported PDF will be encrypted with the password you set. Anyone opening the file on any device will be prompted to enter the password before viewing.
Method 4: Use LibreOffice (Free, Offline, Windows and Mac)
LibreOffice is a free, open-source office suite that can open and export PDFs with password protection:
- Download and install LibreOffice from libreoffice.org (free)
- Open your PDF in LibreOffice Draw (it will prompt you to open it)
- Go to File > Export as PDF
- Click the Security tab in the PDF options dialog
- Set an Open Password and confirm it
- Click Export
This is the best fully offline, free option for Windows users who want to protect PDFs they did not originally create in Word.
Two Types of PDF Password
It is worth knowing that PDFs support two different types of password protection:
- Open password (user password): Prevents anyone from opening the file without the password. This is what most people need.
- Permissions password (owner password): Allows the file to be opened but restricts editing, printing, or copying. Useful for distributing read-only documents.
Most of the free tools above apply an open password. For permissions-based restrictions, you typically need a tool like LibreOffice or a paid Adobe Acrobat subscription.
How Secure Are PDF Passwords?
Modern PDF password encryption uses AES-256, which is very strong for everyday purposes. However, PDF password protection is not foolproof — determined individuals with specialist software can sometimes bypass it. For highly sensitive documents, consider additional layers of protection such as encrypted email or a secure file transfer service.
Sharing the Password Safely
Never send the password in the same email as the protected PDF. Send the file by email and the password separately — via SMS, phone call, or a different email thread.
Related PDF Guides
- How to Compress a PDF for Free
- How to Merge PDFs Without Adobe
- How to Split a PDF into Separate Pages
- How to Sign a PDF Without Printing It
- What Is Two-Factor Authentication?
Related articles: How to Convert a PDF to Word (Free and Easy Methods), How to Convert a PDF to Excel (Free Methods That Actually Work)
