Do you have sensitive information that you need to keep secure? If so, learning how to lock a PDF may be the solution for you. PDFs are a popular format for sharing documents, but they can also be easily accessed and edited by anyone who has the right software. By adding a password or locking feature to your PDF, you can ensure that only authorized users can view and edit your files. In this blog post, we will show you how to lock a PDF. Let’s get started!

How to lock a pdf in 3 different methods

  1. Using Adobe Acrobat
  2. Using Online free pdf editor or converter tools
  3. Using Microsoft word

1. How to lock a pdf using Adobe Acrobat

Adobe Acrobat is a paid program that can be used to create, edit, and convert PDF files. Adobe Acrobat also offers security features that allow you to password protect your PDFs. To lock a PDF using Adobe Acrobat, follow these steps:

  1. Open the PDF in Adobe Acrobat.
  2. Click on the “Protect” button in the toolbar. Select “Password” from the options.
  3. Enter a password and click “OK.” Re-enter your password to confirm and click “OK.”
  4. Your PDF will now be locked with a password. Only users who know the password will be able to view or edit the file.
How to lock a pdf using adobe acrobat
Image from Adobe Acrobat with Protect Pdf option

There are two different types of password security that you can apply to your PDF: user passwords and master passwords. User passwords prevent unauthorized users from opening the PDF, while master passwords prevent unauthorized users from making changes to the PDF. If you want to add both types of security to your PDF, follow these steps:

  1. Open the PDF in Adobe Acrobat. Click on the “Protect” button in the toolbar. Select “Password” from the options.
  2. Enter a user password and click “OK.” Re-enter your password to confirm and click “OK.”
  3. Click on the “Advanced” button. Select “Master Password” from the options.
  4. Enter a master password and click “OK.” Re-enter your password to confirm and click “OK.”
  5. Your PDF will now be locked with both a user password and a master password.

2. How to lock a pdf using an online free pdf editor or converter tools

There are many free online PDF editors and converters that can be used to add security features to your PDF. To lock a PDF using an online tool, follow these steps:

  1. Go to the website of your chosen tool or any PDF editor.
  2. Upload the PDF that you want to lock.
  3. Click on the “Protect” or “Security” button.
  4. Enter a password and click “Apply.”
  5. Your PDF will now be locked with a password. Only users who know the password will be able to view or edit the file.
How to lock a pdf using online free pdf editor
How to protect pdf through whiteout option in A1Office online pdf editor.

Some online PDF editors and converters also offer other security features, such as the ability to add a watermark or encrypt your PDF. If you want to share a pdf while hiding a part of information then you may also use the whiteout option from the A1Office PDF editor tool. Be sure to check the options that are available before you choose a tool. You may also use a converter such as PDF to JPG to convert your PDF to an image from getting copied by others. This can be done using an online converter tool.

3. How to lock a pdf using Microsoft word

Microsoft Word also allows you to password protect your PDFs. To lock a PDF using Microsoft Word, follow these steps:

  1. Open the PDF in Microsoft Word.
  2. Click on the “File” tab and select “Save As.”
  3. Click on the “Tools” button and select “General Options.”
  4. Enter a password in the “Password to open” field. Re-enter your password in the “Confirm Password” field.
  5. Click on the “OK” button.
How to lock a pdf using Microsoft word?
Protect PDF with MS Word

Your PDF will now be locked with a password. Only users who know the password will be able to view or edit the file.

How do I make a PDF read-only?

To make a PDF read-only, follow these steps:

  1. Open the PDF in Adobe Acrobat.
  2. Click on the “Protect” button in the toolbar.
  3. Select “Restrict Editing” from the options.
  4. Check the “Enable copying of content” and “Enable printing of content” options if you want to allow those activities.
  5. Click on the “OK” button.

Your PDF will now be read-only. Users will not be able to make any changes to the file.

How do I lock a PDF in Preview on Mac?

To lock a PDF in Preview on Mac, follow these steps:

  1. Open the PDF in Preview.
  2. Click on the “File” menu and select “Export.”
  3. Click on the “Encrypt” checkbox.
  4. Enter a password and retype to verify it then click “Save.”

Your PDF will now be locked with a password. Only users who know the password will be able to view or edit the file.

How to lock a pdf using preview on Mac?
Image from Mac preview showing how to lock a pdf.

Conclusion

These are three different ways that you can lock a PDF. Be sure to choose the method that best meets your needs. Remember, if you want to add both user and master passwords, you’ll need to use Adobe Acrobat. While for a free experience, use any online pdf editor or converter. If you want to make your PDF read-only, you can do so using Adobe Acrobat or Preview on Mac.

Do you have any other questions about how to lock a PDF? Let us know in the comments below! You can read our other blog on ‘how to password protect an excel file‘ And also be sure to check out our other how-to guides for more tips and tricks.