It is not very common, but sometimes you may need it: PDFs can be encrypted or locked with a password. That means you will have to enter that password every time you want to see the content of that PDF or even print it. It can be useful for example in documents where you want to have passwords for other services.
Unfortunately on the iPhone and iPad it is something that cannot be done yet (unless you have specific applications for it), but we can take a quick look at the steps necessary to encrypt a PDF in macOS. It is not complicated at all, and proof of this is that we can do it with the same Preview application.
Your most sensitive PDFs can be better protected
- Grab any PDF file you have on your Mac that you can test fearlessly with (you can duplicate it to make sure you don’t lose any data in case something happens). Open it, and then go to Menu file Preview and click on ‘To export‘.
- In the dialogue window that appears just above the PDF, we will activate the option ‘Encrypt‘so that we can set a password to lock the file. Remember to remember that password, because otherwise the PDF will be permanently blocked. The format chosen in this dialog box must obviously be PDF.
- Once you have saved it, you will see that the icon of the PDF file will have the symbol of a padlock to indicate that it is protected. Take the test: until you enter the password you will not be able to see it. Not even using macOS quick view.
In TechHow, Use Automator to create an automatic print folder
To remove the password lock from the document, just do the reverse step. We will open the file using Preview, we will access the File menu and we will enter ‘Export’, and we will deactivate the option to establish a password encryption.
iOS and iPadOS can read those documents (they ask for the password without problems), but we do not have the option to add or remove the lock from those systems. Perhaps in the future it will be possible.