In modern times, it is very important to protect personal information from being leaked or accessed by unauthorized parties. You could see that the bank document in PDF format is always protected with a password for security. Besides bank documents, there are many other files containing personal information or business strategy in PDF format needed to be protected. Setting a password for each could be the best way to protect them. 

A password-protected PDF can stop anyone from viewing and editing but those who know the password. Thus, in this post, we will focus on offline and online tools to help you password-protect a PDF on Mac and Windows.

Password Protect a PDF via Online Tools (Mac & Windows & Mobile)

In this part, we will display 5 representative online tools to password-protect PDFs regardless of device, and no need to download or install the software. 


It could be the easiest way to set a password for PDF files in terms of PDF protection using a professional PDF editor, such as ONEPDF. ONEPDF works well on all PDF management. ONEPDF not only enables you to encrypt PDFs but also enables you to convert any format of files. By the way, it is 100% free to use.
Merge PDFs: Better organize and share PDFs

– Split PDFs: Quickly extract information from PDFs you need

– Compress PDFs: Reduce PDFs without losing quality

– Rotate PDFs: Adjust the PDF to its right direction 

– Remove PDFs: Delete unwanted PDFs

OCR PDFs: Scan PDFs to editable document

To password protect PDFs with ONEPDF online, follow these steps:

Step 1. Upload the PDF. Select the needed PDF that you want to encrypt and upload it to ONEPDF PDF Encryption.

Step 2. Set a password. Once the PDF is uploaded successfully, set a password for it and double confirm the password and then click “Protect” to proceed.

Step 3. Save and download the protected PDF. If later you want to unlock the PDF with a password, you can still choose ONEPDF. To remove the password with ONEPDF, it still only needs several clicks.


Smallpdf is a web-based platform that offers a wide range of PDF tools, like PDF converter, PDF merger, PDF scanner and almost all common PDF tools. SmallPDF also allows users to make changes to their PDF files, to add text, images, and signatures to a document, as well as the ability to highlight, underline, and strikethrough text. 

To protect PDFs with SmallPDF, please follow these steps:

Step 1. Go to choose SmallPDF protect tool and click “CHOOSE FILE” to import the PDF to be protected to SmallPDF.

Step 2. On the right of the uploaded PDF, there are two boxes for you to enter the password you want to use to lock the PDF. Now you have double confirmed the password, just click “ENCRYPT PDF”.

Step 3. After the encryption is done, you are allowed to directly download it or choose the output format (Word, Excel, PPT, Image) and then download it.


Soda is another web-based PDF solution to help individuals and businesses work with PDF documents. It has an intuitive interface, making it easy to use for individuals of all skill levels.

To add a password to your PDF document with SodaPDF, please follow these steps:

Step 1. Open Soda Protect PDF tool in any browser and find the PDF that you want to add a password for on your device and import it by clicking “Choose File”.

Step 2. Select a password for your confidential PDF document and enter it on the box and re-enter it to confirm its encryption password. Click “PROTECT” to start setting.

Step 3. Download the password-protected PDF as you need.


iLovePDF makes you work PDFs quickly and easily. You can convert, edit, merge, and compress PDF files with it. Additionally, iLovePDF offers a range of security features to protect users’ documents. To add passwords to PDFs, follow these steps:

Step 1. Choose iLovePDF PDF Protect Tool and add the sensitive PDF that you want to encrypt to it.

Step 2. Here you can start setting a password for the added PDF and enter and repeat your chosen password in the boxes on the right.

If you have one more file to encrypt, tap the plus icon to add more. Finally, tap Protect File to start encryption.

Step 3. Now you can choose to download the protected PDF or share the download link.


PDFcandy is another web-based tool that allows you to convert, merge, split, compress, and edit PDF files. You can also merge several PDF files into one or split a single PDF file into multiple files. Additionally, you can compress large PDF files to make them smaller and easier to share, as well as add watermarks, page numbers, and password protection to your PDF files.  

To password protect PDFs with PDFCandy online, follow these steps:

Step 1. Add the PDF file you want to protect from your device or upload the PDF from Dropbox or Google Drive.

Step 2. Tap on the green setting icon and you will be asked to set a password for protecting PDF. Enter your chosen password twice and apply them and then click Protect PDF.

Step 3. Now the PDF has been protected with a password and you can download it to your device.

Password Protect a PDF via Offline Tools on Windows or Mac

Offline PDF password tools are favored for no connection needed and higher level of security. So here we are also going to introduce some offline tools to help you protect PDF files. Here we go.

Adobe Acrobat DC

When it comes to PDF editing software, undoubtedly, Adobe Acrobat DC could be the best one for most users. Adobe Acrobat DC  is equipped with a suite of tools for creating, editing, and managing PDF documents. It includes a range of features such as document conversion, digital signature capabilities, form creation, and much more.

To encrypt a PDF using Adobe Acrobat DC on Windows or Mac, you can follow these simple steps:

Step 1. Open the PDF document that you want to encrypt in Adobe Acrobat DC. And Click on the “Tools” tab in the top menu bar, and then select Protect > Encrypt, and then select “Encrypt with Password.”

Step 2. Now a Password Security page jumps and you can set two kinds of password here. One is the document open password and the other one is the password for editing or printing a PDF document. Select one you need, or both to start setting a password for the PDF. Enter a password for the PDF document in the box and Confirm the password by re-entering it in the “Verify Password” field.

Step 3. Click on “OK,” and then “Save” the document to apply the encryption. Close the file and then open it and then a window pops up to ask you to enter the password you set before to open the file.


UPDF is a free PDF editor software that allows users to view, edit, and convert PDF files. It also offers a feature to encrypt PDF documents.

Here is how you can password protect a PDF with UPDF:

Step 1. Download and install UPDF on your computer. Launch UPDF and click on the “Open” button to select the PDF file that you want to encrypt.

Step 2. Once the PDF is loaded, click on the “Protect Using Password” tab on the right of the UPDF toolbar.

Step 3. Like Adobe Acrobat, UPDF also allows you to set a password for document open and PDF permission to encrypt the document. You can  choose which one should be restricted.

Step 4. After setting the password, click on the “Apply” button to apply the encryption. Finally, click on the “Save” button to save the encrypted PDF file.

Wondershare PDFelement

PDFelement is a top-notch PDF editor integrated with a variety of useful PDF editing tools. One of the core features of PDFelement is its ability to convert PDF files to other file formats. Users can easily convert PDFs to Word, Excel, PowerPoint, HTML, and other popular file formats. Other features, such as PDF splitting, PDF merging, are also included in it.

Here is how you can password protect a PDF with PDFelement

Step 1. Open the PDF that you want to protect in PDFelement.

Step 2. Once the PDF is opened, go to Protect from the top toolbar and then choose Set Password. Enter the password for your PDF and then save it.


Password Protection is the most secure and common way to protect PDFs. After reading through this post, you have noticed that there is indeed more than one way to protect sensitive and confidential PDF files via adding a password. With any of the PDF tools we have mentioned above, you can easily add a password for your PDF document.

Which one to choose depends on your need or the devices you are used to use. Online tools are convenient to use and no matter what devices you are holding, you can always access them only if you have an internet connection. ONEPDF Online tool lets you encrypt a PDF effortlessly. Offline PDF tools usually have more advanced features than online ones. Adobe Acrobat DC could be your ideal choice.


Question 1. How to Encrypt PDFs on Mac in Preview?

To encrypt a PDF on Mac, you can use the Preview, the built-in PDF viewer of the macOS operating system. 

First, right-click on the PDF and open it using Preview. Choose File > Export > Security Options… and enter the new password you will use for the PDF and re-enter it again. Finally, click OK for encryption.

Question 2. How to Password Protect a PDF Free?

Besides the free online ONEPDF editor, if you happen to have Microsoft Word installed on your Windows, you can password protect a PDF with it free.

Open the PDF in Microsoft Word and go to File >Export > Option… and under the PDF options, choose “Encrypt the document with a password”. Tap OK and you will see a window called Encrypt PDF Document for you to enter the password you choose for the PDF. After entering the password, tap OK and then finally tap Publish.