Password protect a PDF

It’s totally free, easy and super quick to password protect a file with Adobe Acrobat online. Just choose your PDF by clicking Select a file above, or dragging it into the dropzone box, then set a password and download your new document. From there, it’s ready to share safely.

You should find that you can password protect most PDFs using Acrobat online. However, you might find that some files appear with a “bad parameter” error message. If this happens, don’t sweat it – just save a copy of your file, reupload it, and try again.

The internet isn’t always a safe place, but Adobe Acrobat helps keep your documents as safe as can be. When you password protect a PDF or other document with Adobe Acrobat, we encrypt it too for extra security. But you can access additional security measures with Adobe Acrobat Pro.

If you want to create a strong password, follow best-practice advice. For starters, each password should be unique. Then, try to make the password longer. Don't use any personal information or the type of everyday words someone may be able to guess.

Assembling seemingly random words with zero connection can be one idea. And try to increase its complexity with the addition of numbers and special characters.

If someone sends you a password-protected file, you'll be prompted to enter the password when you try to open it. Enter the password and hit OK and you'll be able to access the file. If the document owner has Adobe Acrobat Pro, they can also remove the password in three easy steps using the Unlock Tool.

Password protection prevents anyone who doesn't have the password from accessing the document. If you want them to open the PDF, you must provide them with the password.

Encryption works in a similar way but is more complex. Once you encrypt a document, it 'scrambles' the page content, rendering it as cipher text, which you cannot read. For a user to be able to access this, you need to give them a digital encryption key. Once the user enters the key – which often takes the form of a password or digital certificate – the text will return to normal so they can read it.

When you password-protect a PDF using Acrobat online tools, it encrypts the file for added security. For those with Adobe Acrobat Pro, you have stronger security at your disposal. Encrypt PDFs with certificates and adjust permissions so users can access but not edit the PDF. Ready to get started? Get a 7-day free trial of Adobe Acrobat Pro for Mac or Windows.