How to Password Protect a PDF — Secure PDF for Free

6 min readAug 12, 2022



To password protect a PDF file, you will need a dedicated PDF tool with an encryption feature. Adding passwords to PDFs is not as difficult as you may have thought. It only takes seconds and several steps to do so. Here in this article, we’ll show you how to password protect a PDF, for both Windows and macOS.

How to Password Protect a PDF on Windows

Many PDF applications have a good performance on Windows systems. They help solve all common PDF issues without any limits. In this part, we will introduce you to two top-rated PDF software warmly welcomed by Windows users. One is SwifDoo PDF, and the other is Adobe Reader.

How to Password Protect a PDF with SwifDoo PDF

SwifDoo PDF is one of the most full-featured PDF software capable of solving all PDF-related problems. It works well on all Windows systems, from XP to 11. Actually, if you’re a fan of Windows and looking for a handy PDF tool, we strongly recommend SwifDoo PDF.

SwifDoo PDF makes it very simple to password protect a PDF and reduces expenses to the minimum. That’s why we put it in first.

Within only three steps, you can password protect a PDF. Here’s how:

Step 1. Download SwifDoo PDF and run it on your computer, then open the PDF file that you need to add a password;

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Step 2. Check the top navigation bar and click Protect > Encryption;

Step 3. Select the password type that you want to set, then enter a password. After setting down, click OK to confirm the change.

Note: In the Encryption window, SwifDoo PDF leaves the Replace Existing Files box checked by default. Remember to uncheck it if you don’t want to overwrite the original document.

SwifDoo PDF provides you with two types of passwords. One is Open Password to restrict the opening of a PDF file, and the other is Owner Password to set editing-related restrictions. You can choose one according to your actual need.

How to Password Protect a PDF in Adobe Reader Free

Adobe Reader is a free version of Acrobat to view, create, fill, and print PDF files. In fact, it’s not only available on Windows, but also on macOS. Adobe Reader is not as powerful as Acrobat Pro, but it helps a lot if you only need to add a password to a PDF.

Here are specific steps:

Step 1. Install Adobe Reader on your computer, then open a PDF file;

Step 2. Click File in the top navigation bar, then select Password Protect;

Step 3. There are two options: Editing and Viewing. The former is used for limiting editing actions and people can open and view the file. While the latter limits viewing, so anyone who doesn’t have the password cannot even open it;

Step 4. Enter a password, then click Apply.

Note: Your password should contain at least six characters. There’s also a notice which indicates the security level of your password, including best, strong, medium, and weak.

How to Password Protect a PDF on Mac

Since Mac users have a default PDF viewer (Preview) that can meet all basic editing needs on PDF files, they don’t have to download any third-party software. Preview’s primary purpose is to offer users an easy way to check photos and PDF files, and later it began to enable users to make simple editing on PDF files.

Preview is freeware, so you don’t have to spend a penny to add a password to a PDF file. Only a few steps are needed to make PDF files protected.

Here’s how to password protect a PDF on Mac:

Step 1. Launch Preview and open a PDF file;

Step 2. Click File > Export, then choose a password type;

Step 3. Check the encrypt box, then enter a password and type again to verify;

Step 4. Click Save to confirm the change.

It’s much more convenient for Mac users to use Preview because they don’t need to download other tools or pay for them, which saves time a lot and reduces unnecessary expenses.

How to Password Protect a PDF Online

The three methods we’ve mentioned above are all offline solutions, how about using online tools? By using an online PDF editor, you don’t have to waste time finding or downloading other applications. Consequently, you won’t worry about any computer viruses or downloading unwanted software.

Online utilities become more and more popular for their high convenience. No downloading or installation actions are needed, but a PDF file can also be edited to whatever they want.

Here, we’re going to take PDF2GO as an example to teach you how to password protect a PDF online:

Step 1. Open PDF2GO’s protect PDF page;

Step 2. Click Choose File to upload the PDF file that you want to protect;

Step 3. Choose to set an open password or permission password. Enter a password and repeat it;

Step 4. Click on the “ Start “ button to apply your settings.

Note: The open password and permission password cannot be the same.

Except for password-protecting PDF files, PDF2GO also offers a more reliable way to ensure PDF files’ security. It enables users to rasterize PDFs to merge all contents into a non-searchable layer. Thus, you can efficiently prevent others from editing the document.

Let’s Wrap It Up

In this post, we offered you a step-by-step guide on how to password protect a PDF. With both online and offline, Windows and Mac operating systems covered, there’s no doubt that most of you can find a solution to add passwords to those important PDF documents.

  • Two types of passwords supported
  • 100% safe & secure to prevent all edits
  • The easiest way to password protect a PDF for free

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Windows 11/10/8.1/7/XP

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I’m fascinated by the influence of evolving technologies, computer software/hardware as well as social behavioral norms.