Install a Program or Go Online

These four programs must be installed on your computer before you can use them to password protect a PDF file. You might even already have one of them, in which case it’ll be quick and easy to just open the program, load the PDF, and add a password.

However, if you’re looking for a much faster (but still free) way to make the PDF have a password, skip down to the next section below for some free online services that can do the exact same thing.

Password Protect a PDF With PDFMate PDF Converter

One absolutely free program that can not only convert PDFs to other formats like EPUB, DOCX, HTML, and JPG but also put a password on a PDF, is PDFMate PDF Converter. It works on Windows only.

You don’t have to convert the PDF to one of those formats because you can instead choose PDF as the export file format and then change the security settings to enable a document open password.

Choose Add PDF at the top of PDFMate PDF Converter. Select the PDF you want to work with, and then choose Open. Once it’s loaded into the queue, choose PDF from the bottom of the program, under the Output File Format: area. Select Advanced Settings near the top right of the program. In the PDF tab, put a check next to Open Password, and then enter a password in the field to the right. You can optionally choose Permission Password, too, to set up a PDF owner password to restrict editing, copying, and printing from the PDF. Choose Ok to save the PDF security options. Select Output Folder toward the bottom of the program and then pick where the password protected PDF should be saved. The PDF can be saved to the same location as the original or you can choose Custom to pick a different folder.  Use the big Convert button at the bottom of PDFMate PDF Converter to save the PDF with a password. If you see a message about upgrading the program, just exit that window. You can also close down PDFMate PDF Converter once the Status column next to the PDF entry reads Success.

Password Protect a PDF Using Adobe Acrobat

Adobe Acrobat can add a password to a PDF, too. If you don’t have it installed or would rather not pay for it just for this, feel free to grab the free 7-day trial.

You can optionally choose Permission Password, too, to set up a PDF owner password to restrict editing, copying, and printing from the PDF.

The PDF can be saved to the same location as the original or you can choose Custom to pick a different folder.

Go to File > Open to locate the PDF that should be password protected with Adobe Acrobat; select Open to load it. You can skip this first step if the PDF is already open. Navigate to File > Properties. Go into the Security tab. Next to Security Method:, select the drop-down menu and choose Password Security. At the top of that window, under the Document Open section, put a check in the box next to Require a password to open the document. Enter a password in that text box. At this point, you can continue through these steps to save the PDF with just a document open password, but if you also want to restrict editing and printing, stay on the Password Security - Settings screen and fill out the details under the Permissions section. Choose OK and confirm the password by typing it again in the Confirm Document Open Password window. Choose OK on the Document Properties window to return to the PDF. Save the PDF to write the open password to it. You can do that via File > Save or File > Save As.

Password Protect a PDF With Microsoft Word

It might not be your first guess that Microsoft Word can password protect a PDF, but it’s most certainly capable of doing so! Just open the PDF in Word and then go into its properties to encrypt it with a password.

At this point, you can continue through these steps to save the PDF with just a document open password, but if you also want to restrict editing and printing, stay on the Password Security - Settings screen and fill out the details under the Permissions section.

Use the File > Open menu to browse for and open the PDF. Choose OK on the message about Microsoft Word converting the PDF into an editable form. Navigate to File > Save As > Browse. From the Save as type: drop-down menu that probably says Word Document (. docx), choose PDF (. pdf). Name the PDF and then choose Options. Select the box next to Encrypt the document with a password from the bottom of the prompt. Choose OK. Enter a password for the PDF twice. Choose OK to save and exit that window. Pick where to save the new PDF file and then select Save. You can now exit any open Microsoft Word documents that you’re no longer working in.

Password Protect a PDF Using OpenOffice Draw

OpenOffice is a suite of several office products, one of which is called Draw. By default, it can’t open PDFs very well, nor can it be used to add a password to a PDF. However, the PDF Import extension can help, so be make sure to install that extension once you have OpenOffice Draw on your computer.

Open OpenOffice Draw and go to File > Open. Select and open the PDF file you want password protected. It might take several seconds for Draw to open the file, especially if there are several pages and lots of graphics. Once it’s fully opened, you should take this time to edit any text that might have been altered when Draw attempted to import the file. Go to File > Export as PDF. Access the Security tab and select Set passwords. Using the first two text boxes, type the password that you want the PDF to have to prevent someone from opening it. You can also put a password in the last two fields if you want to protect the permissions from being changed. Choose OK to save and exit that window. Select Export and then save the PDF, picking a custom name and location if you so choose. You can now exit OpenOffice Draw if you’re done with the original PDF.

Password Protect a PDF Using an Online Service

Use one of these websites if you don’t have those programs from above, aren’t willing to download them, or would just prefer to add a password to your PDF in a faster way.

It might take several seconds for Draw to open the file, especially if there are several pages and lots of graphics. Once it’s fully opened, you should take this time to edit any text that might have been altered when Draw attempted to import the file.

You can also put a password in the last two fields if you want to protect the permissions from being changed.

Soda PDF lets you upload from your computer or load the file directly from your Dropbox or Google Drive account. Smallpdf is extremely similar, except it defaults to 128-bit AES encryption. Once your PDF is uploaded, the encryption process is quick, and you can save the file back to your computer or your account at Dropbox or Google Drive. FoxyUtils is one more example. Just upload the file from your computer or a cloud storage site, choose a password, and optionally put a check in any of the custom options like to allow printing, modifications, copying and extracting, and filling out forms.

Encrypt PDFs on macOS

Most of the programs and all of the websites from above will work just fine for password protecting PDFs on your Mac. However, they really aren’t necessary since macOS provides PDF encryption as a built-in feature!

Open the PDF file to have it load in Preview. If it doesn’t open automatically, or a different application launches instead, open Preview first and then go to File > Open. You can also edit PDFs on a Mac with Preview. Navigate to File > Export as PDF. Name the PDF and choose where you want to save it. Put a check in the box next to Encrypt. If you don’t see the “Encrypt” option, use the Show Details button to expand the window. Enter the password for the PDF, and then do it again to verify. Choose Save to save the PDF with the password enabled.