Do you need to sign a PDF document that has been sent to you but, having never done anything like this before, you have no idea how to do it and, above all, which tools to use to do it? If that’s the case, you’ve come to the right place at the right time.
In the following lines, in fact, we’re going to discover together how to sign a PDF document acting from your computer, smartphone and tablet. I anticipate that all you have to do is use some applications for computers or mobile devices suitable for the purpose, all very simple to use. If you don’t want to install new tools on your devices, you can also consider using online services.
In short, it’s all much simpler than you might think. Watch out, though, for the legal validity of the signature, which I’ll tell you about in a few lines. So? How would you like to put the chatter aside and start getting busy? Everything is explained below.
Preliminary information
Before we get into the heart of the tutorial, going to explain how to sign a PDF document, there are some preliminary information about it that you absolutely need to know.
In case you don’t know, there are different types of electronic signatures, each with a different level of legal validity.
Electronic signature – this is a simple graphic reproduction of the signature that has no intrinsic legal value, considering that there are no methods of electronic recognition of the same. Its legal validity must be decided by a judge, who evaluates its authenticity case by case.
Advanced electronic signature – this is a type of signature created by certain software. It has full legal force, except for real estate contracts. The signer has direct and exclusive control over the signature and can prove its authenticity using a device he or she owns.
Qualified electronic signature or digital signature – is the most advanced type of electronic signature, it is created through specific signature kits sold by recognized certification bodies. The legal value is full and verification of authenticity is guaranteed by an encrypted signature system with a public key.
How to sign a PDF document with digital signature
Now that you have clear ideas about the various types of existing electronic signature, I’d say it’s time to take action. So, if you ended up on this guide because you are interested in understanding how to sign a PDF document with a digital signature, therefore having legal value, you must know that you have to buy a special kit from one of the many providers available.
To give you a practical example, I’ll tell you about the solutions offered by Aruba, which allows you to buy both the classic physical signature kits, in which the signature certificate resides in a physical SIM to be connected to the PC via USB key or card reader, and the digital signature kits, in which the signature certificate is hosted on secure servers of the company and, therefore, can be used (through the insertion of OTP codes) not only from the computer, but also from smartphones and tablets through applications designed for this purpose.
To sign a PDF document with Aruba from your PC you have to use the software ArubaSign, available for Windows, macOS and Linux. Once in use, you need to select the document to be signed and the signature format to be applied to it, indicate what type of signature to use, specify the relevant information in the fields provided, decide whether or not to apply the time stamp and confirm everything. The same thing can be done from smartphones and tablets, using the specific app for Android and iOS/iPadOS. For all the details, I invite you to read my tutorial on how the Aruba Digital Signature works.
How to sign a PDF document for free
Let’s see, now, how to sign a PDF document for free, that is, how to affix the electronic signature acting from the computer, using special programs for Windows and macOS, but that do not allow to have an implicit legal validity of the signed files.
How to sign a PDF document with Adobe Reader DC
Among the most famous and complete PDF management software that gives you the possibility of applying an electronic signature to your documents is Adobe Reader DC. As you can easily guess from its name, this is a solution distributed by Adobe, the same company that developed the PDF format. It works both on Windows and macOS and allows modifying PDFs that are given to it in various ways.
Basically, the program in question is free, but some more advanced features are reserved for subscribers to the paid version, called Acrobat DC, which has prices starting from 18.29 euros/month (but you can try it for free for 7 days). To download the program to your computer, go to its website and click on the Download Acrobat Reader button.
After the download is complete, if you are using Windows, open the Acrobat Reader DC executable you obtained and, in the window that appears on your desktop, click the Yes button; then wait for the download of the components to make the software work and click the Finish button.
If you are using macOS, open the installation package and double-click on the .pkg file in the window that appears. Next, press the Continue button (twice in a row), type in your Mac user account password, click the Install software button and finish the setup by clicking the Close button.
Now that you see the program’s window on your screen regardless of your operating system, choose whether you want to set the software as your default PDF reader or not, then click on the File menu at the top left of the screen, click Open and select the PDF file you want to work on.
Then, in order to sign a PDF document with Adobe Reader DC, click the Fill in and Sign heading in the right-hand sidebar, select the Signature heading at the top and choose the Add Signature option from the menu that opens.
Decide, then, whether to get the signature to be inserted on the document by typing it with the keyboard, drawing it with the mouse or touchpad, or loading its image, adjust the related settings and click the Apply button.
Finally, click on the point of the document where you want to add the signature, resize it if necessary using the signature slider and save the signed PDF by clicking on the File menu at the top left and choosing Save As to create a new file or Save to overwrite the current PDF.
How to sign a PDF document with Mac
If you own a Mac, you can sign a PDF document even without the use of third-party programs. You probably didn’t know this, but you should know that on macOS there is Preview, the default application of Apple’s operating system for viewing and editing images and PDF documents, which also provides its users with a special function for digitally signing documents in the format in question.
That said, to sign a PDF document with Mac, open the file you want to work on by double-clicking on its icon. If the document does not open in Preview but with another program, right-click on its icon, select Open with from the menu that appears and then select Preview.
Now that you see the PDF on your screen, click on the pencil button located on the toolbar at the top and click on the signature button located a little further down.
Through the menu that appears, select the Trackpad tab, if you want to draw your signature using the trackpad, or the Camera tab, to write your signature on a sheet of paper to be placed in front of the Mac’s webcam and allow its identification. Then click on the Finish button.
Once the signature has been created, to add it to the document, click on it from the signature menu displayed by clicking on the signature button and drag it to the desired location in the PDF. If you feel it is necessary, you can also resize it by moving the sliders.
When you’re done, save the signed PDF document by clicking on the File menu, top left, and selecting the Save to it item attached to it.
How to sign a PDF document online
If you don’t want to use “real” software, you can consider to sign a PDF document online, using web services that work directly from the browser window, from any operating system. Even in this case, we are talking about solutions that do not guarantee the legal validity of signed files.
PDFCandy
If you want to sign a PDF document without printing it, acting via the Web, I recommend you to resort to the use of PDFCandy. It is an online service through which you can act on PDF files by converting, splitting, lightening, unlocking, etc. and, of course, signing them.
Basically it’s free, but you can’t upload files larger than 500 MB and there are other limitations. Eventually, you can get around this by subscribing to one of the paid plans (with costs starting at 6 euros/month). Note, then, that the privacy of users is protected, since the documents uploaded to its servers are automatically deleted within a few hours of upload.
To use PDFCandy, go to the service’s home page, click on the Add File button and select the PDF you want to work on. Alternatively, drag the file directly into the browser window. You can also download the PDF from your Google Drive or Dropbox account by clicking on the appropriate icons.
Once the upload is completed and the editor of the service is displayed, click on the signature button in the left sidebar, press the Add new signature button in the menu that appears and draw your signature in the appropriate area, using the mouse or the touchpad, then click on the Save button.
Next, move the mouse pointer over the newly created signature you find in the menu on the left and click the (+) button that appears on it to add it to the document, then drag it to the place in the PDF where you want to place it and adjust its size using the sliders that appear around it.
To conclude, save the newly signed PDF by clicking the Export File button in the upper right corner and proceed with the download of the edited document by pressing the Download File button. You can also decide to save the resulting compressed PDF to Google Drive or Dropbox by selecting the icon of the cloud storage service you are interested in.
Other solutions for signing a PDF document online
Looking for more solutions to sign a PDF document from the browser window? Then take a look at the ones included in the list below. I’m sure you’ll be able to find something that will satisfy you.
iLovePDF – is a popular online service that allows you to act on PDF documents in various ways, so not only signing them, but also splitting them, converting them, etc.. Basically it is free and does not require registration, but it does not allow you to upload files weighing more than 100 MB. To get around this limitation you have to switch to one of the paid plans (with costs starting from 6 euros / month), which allow you to unlock other extra features. Regarding privacy, it should be noted that files uploaded to the service’s servers are removed within a few hours.
Sejda – is an online service that allows you to work on PDF documents in various ways, including signing them. It is very easy to use and free of charge. It allows uploading files with a maximum size of 50 MB and with a maximum of 200 pages, but does not allow more than three operations per hour. It should be noted that users’ privacy is protected, since files are automatically removed from the service’s servers after two hours.
PDF24 – is another web service for signing PDF documents, as well as making various changes to the document type in question. It is free of charge and does not place limitations on the maximum weight of files and the number of documents you can act on. Besides, the privacy of the users is protected as all files uploaded to the service’s servers are removed in the short term.
How to sign a PDF document with Android
You don’t have a computer at hand and would like to understand how to sign a PDF document from your Android smartphone or tablet?
In this case, if you want to sign a document with legal validity, you have to use a remote electronic signature service, like the one I mentioned earlier, through the relevant application.
If, on the other hand, you’re not interested in providing certain legal validity to the document, you can turn to Adobe Fill & Sign. It’s an app that was also developed by Adobe, the same software house of Adobe Reader DC that I told you about in the step at the beginning of this guide. It’s free and allows you to fill, sign and send PDFs.
To download and install the app on your device, go to the relevant section of the Play Store and tap on the Install button. If you are using a device that does not have the Play Store, you can download the app from alternative stores.
Next, launch the app by selecting its icon added to the home screen and/or drawer, tap on the Continue button located at the bottom and the (x) button located in the top right corner to skip the registration step.
At this point, to sign a PDF document with Android, select the file of your interest by tapping on the button with the sheet and the (+) symbol in the middle or by opening the recent documents at the bottom of the screen, then tap on the button with the fountain pen at the top and tap on the option Create signature from the proposed menu.
Then draw the signature by swiping your finger on the screen and when you are done, tap on Finish. After that, tap the button with the fountain pen again and select the signature you just created from the menu that opens to add it to the document. Then move it to the place you prefer and if necessary adjust its size using the slider.
When you’re done editing, tap on the arrow icon located in the top left corner to return to the app’s main screen and overwrite the current file. Alternatively, you can share the PDF to other apps or locations by tapping on the share icon located in the top right corner.
How to sign a PDF document with iPhone and iPad
Do you own an iOS/iPadOS device and, therefore, would like to understand how to sign a PDF document with iPhone and iPad? I’ll satisfy you right now!
If you want to sign a document with legal validity, you have to use a remote electronic signature service, like the one I told you about in the dedicated chapter of this guide, installing the related application on your device.
If, on the other hand, you don’t want to give certain legal validity to the PDF, you can do everything directly via File, which is the default file manager on Apple’s mobile devices (if the app is removed, it can be downloaded again for free from the relevant section of the App Store). Not everyone knows this, but through the app in question you can also view and edit PDFs.
To use it, open the File app on your device by selecting the File icon (the one with the blue folder and white background) on the home screen and/or in the App Library, then go to the location where the PDF you want to sign is stored, select its icon and, once opened, tap the button with the pencil at the top. If the PDF you want to sign is stored elsewhere, open the app you are interested in, tap on the share icon and choose the File option from the menu that opens.
At this point, press the (+) button located at the bottom right corner, choose the Signature option from the menu that appears, write your signature by swiping your finger on the screen and tap on the Finish option located at the top to affix the signature to the document.
Then drag the signature to the most appropriate place in the PDF, adjust its size if necessary using the sliders that appear around the selection rectangle and save the modified file by tapping on the Finish button in the upper left corner.