Posted on 

May 30, 2022

Ditch Paper Workflows: How to Electronically Sign a PDF

Ruzica Mastelic
Content writer

In this day and age, why would you waste precious time and resources printing documents that need to be signed? There are much more streamlined ways to handle them. That’s why you’re here, looking to learn exactly how to electronically sign a PDF. You’ll find your answers, no matter the operating system you’re working on. But you’ll also learn the difference between electronic and digital signatures, and why this could be important to you.


  1. Electronic vs digital signatures
  2. How to electronically sign a PDF
  3. How to digitally sign a PDF
  4. Using Contractbook for digital signatures

Electronic signatures vs digital signatures

Electronic and digital signatures are not the same thing. But people often confuse them, probably because it could be said that a digital signature is a subset of electronic signatures. 

Why is it important for you to know this? Unlike an electronic one, a digital signature is encrypted. This means it’s a lot more secure to use, especially for businesses. 

And now that you’re aware of this difference, we can jump to teaching you how to electronically sign a PDF.

How to electronically sign a PDF

You have your document ready, but no know-how as to how to electronically sign a PDF. It’s not a complicated process, but it varies slightly depending on which operating system you’re using.

How to sign a PDF document on Windows

If you’re using Windows, the easiest way to sign a PDF is through Adobe Reader. This is what you need to do:

  1. Open the document in Adobe Reader.
  2. Navigate to the right pane and click the button that says Fill & Sign.
  3. Click Add Signature.
  4. Choose among the following three options: Type, Draw, or Image. 

If you choose Type, you’ll be able to type in your name and select a handwritten font. This will then be converted to a signature. Just keep in mind that it won’t look like your actual signature. 

If you opt for Draw, you’ll be prompted to use your mouse or touch screen to create a signature. This will look like your actual signature, but it can be a bit difficult to use.

There’s also the option to select Image and upload your actual signature. This is a bit more time consuming, since you’ll need to sign a piece of paper and then scan it. But you’d only have to do it once.

  1. Click Apply.
  2. Choose where you want the signature to appear in the document.
  3. Click File and then Save.

And that’s it. You’re done. But if you want to know how to sign a PDF document on Mac, just read on.

How to sign a PDF on Mac

If yours is a Mac computer or laptop, you’ll have no problem creating an electronic signature. Namely, you won’t even have to use third-party software. Here’s how to sign a PDF on Mac straight from your Preview application:

  1. Open the document in Preview.
  2. Find and click the button that looks like a toolbox. It’s the Show Markup Toolbar.
  3. Click the Sign button.
  4. To create your signature, choose between using your trackpad and your webcam.

If you choose the trackpad, you’ll be able to sign by dragging your finger over it. While these generally make your signature appear clumsy, Force Touch trackpads are a lot more accurate. 

If you opt for your webcam, you’ll use it to scan a piece of paper with your signature on it. Preview will save this for future use, so you’ll only need to do it once.

  1. Click Sign.
  2. Resize the signature image if necessary.
  3. Drag it around to choose where it will be positioned.
  4. Click File and then Save.

That’s it. Now you know how to sign a PDF on Mac.

What if you want to sign digitally?

You wanted to know how to electronically sign a PDF. But if you want a higher level of security, you’ll need to learn how to sign digitally instead of electronically. The process is a bit more complicated because it involves getting a digital ID. Here’s how to do it:

  1. Create an image of your signature.
  2. Open the document in Adobe Reader. 
  3. Click Tools and then Certificates.
  4. Select the Digitally Sign option. 
  5. Choose where you want your signature to appear.
  6. This will open a dialog box titled Add Digital ID. Choose the option for creating a new one.
  7. In the new dialog box, fill in your information and enter a password.
  8. In the dialog box titled Configure Signature Appearance, select the Imported Graphic option.
  9. Locate the image with your signature.
  10. Enter your password and click Sign.

And that’s how you sign digitally instead of electronically.

How to edit a digitally signed PDF document

What if the PDF is already signed, but you want to edit it? If it’s signed electronically, you won’t have any trouble doing this. But if it contains a digital signature, it’s locked for any further tampering. You can try all you want, but you won’t be able to make any changes.

Why is this? It’s simple, really. The whole point of a digital signature is to ensure its authenticity and the authenticity of the document in question. If you were allowed to make changes to it, that would make the whole system pointless.

So if you’re wondering how to edit a digitally signed PDF document, sadly, you’ve lucked out. 

How to combine digitally signed PDF files

What if you have multiple digitally signed PDFs that you want to merge into a single PDF? Just like editing them, this is also not possible.

How come, you might wonder. It’s for the same reason that making changes to the document itself is not allowed. Signing a PDF digitally locks it to prevent you tampering with the document. If you think about it, it makes a lot of sense. What would happen if people could easily add new pages to an existing document, one that’s already been signed? They’d be able to change the terms of the contract itself.

If there was a way, you’d have no trouble finding out how to combine digitally signed PDF files. But there simply isn’t.

Using Contractbook for digital signatures

Now that you know how to electronically sign a PDF, you might stick with the decision to do so. But if you’ve changed your mind and would prefer a higher security level, digital is the way to go. We at Contractbook offer top-class software for just such purposes. Our digital signatures are not just legally binding, but easy to create as well. To make use of all their benefits, you only need to get in touch.

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