An electronic signature (or e-sign) has become an increasingly common mode of verifying one’s identity these days. Part of the reason for this is that an electronic signature eliminates the need for in-person presence and allows the remote signing of documents.

electronically signing a pdf document
IMAGE: DocuSign (Unsplash)

While using a macOS or Windows computer is one way to sign PDF documents electronically, if you need to do it more often—and while you’re on the go—you’d want to do it on a mobile device.

So in this guide, we’ll demonstrate the different ways to sign PDF documents on Android and iOS/iPadOS devices.

How to Electronically Sign PDF Documents on iPhone or iPad

One of the easiest ways to sign a PDF document on an iPhone or iPad is to use the Files app. Files is Apple’s default file management app for devices running iOS and iPadOS that lets you access all your files from local and cloud storage services all in one place.

Since it comes pre-installed on iOS and iPadOS, you can follow the steps below right away to sign your PDF documents on your iPad or iPhone electronically:

  1. Open the Files app on your iPhone or iPad.
  2. Head over to the folder that contains the PDF file you want to sign.
  3. Tap on the PDF to open it using File’s built-in PDF reader/editor.
  4. Once the PDF is open, tap on the markup tool (pen) icon in the top-right corner to bring up markup features. Fill out any form fields as required.
    electronically sign a pdf document on iphone
  5. Hit the plus (+) button and select Signature from the menu.
    electronically sign a pdf document on iphone
  6. If you’ve never created a signature, the app will present you with a blank screen. Use your fingers to draw out your signature on this screen.
    electronically sign a pdf document on iphone
  7. When you’re done, click Done.

As soon as you do that, Files will save your signature and add it to your document. You can then click and drag it to move it to the signature field on the form or PDF. Similarly, you can also resize the signature by dragging the box around it outward or inward.

Besides, you have the option to change the signature color as well. For this, click on the color picker icon and select a color from the color palette.

Finally, when you’re satisfied with your signature, hit Done on the top-left to save the signed PDF document.

Other iPhone and iPad Apps to Sign PDF Documents

How to Sign a PDF Document on Android

Unlike an iPhone or iPad, the default file manager that comes pre-installed with most Android skins doesn’t offer a built-in PDF signing feature. And therefore, if you need to sign a PDF form or document on your Android phone or tablet, you need to use a third-party PDF editor.

For the purpose of this guide, we’ll use Adobe Acrobat Reader DC, which is a free app—for the most part—that lets you sign PDFs for free. So head over to the link below to download Adobe Reader on your Android from the Play Store.

Download: Adobe Acrobat Reader DC

With the app installed on your phone or tablet, use the steps below to sign your PDF documents using the Acrobat Acrobat Reader:

  1. Open the file manager of your choice on your Android phone or tablet and head over to the folder with the PDF file you want to sign.
  2. Click on the PDF, and when prompted to choose an app to open it, select Adobe Acrobat. If you don’t get this option, simply open Adobe Acrobat DC, and you should see all the PDFs on your device.
  3. With the PDF open, click on the pen icon at the bottom of the screen and select Fill & Sign from the menu.
    electronically sign a pdf document on android
  4. Tap the signature icon on the bottom-right corner of the toolbar.
    electronically sign a pdf document on android
  5. Now, depending on whether you want to create a signature or just your initials, tap on either Create Signature or Create Initials.
    electronically sign a pdf document on android
  6. Irrespective of what option you choose, you’ll be taken to a new screen where you’ll need to draw your signature or initials. Adobe Reader will give you the following three options to do this:
    • Draw: It lets you draw out your signature/initials. You can choose from a selection of signature styles.
      electronically sign a pdf document on android
    • Image: It lets you upload the signature image from your device.
    • Camera: It lets you take a snapshot of your physical signature or initials.
  7. Once you’ve created your signature or initials, click on the Done button.

Adobe Reader will now save your signature/initials and ask you to tap on an area in the document to add them. With your signature added, you can then move it around or use the arrow to increase or decrease its size.

electronically sign a pdf document on android

When you’re happy with your signature, tap the tick button on the top-left to save the document.

electronically sign a pdf document on android

Other Android Apps to Sign PDF Documents

Sign PDF Online for Free – Non-app Solutions

Besides using dedicated PDF eSign apps on your iPhone or Android phones, you can also use free (or paid) online PDF tools for signing PDFs electronically. Below are some of the best online PDF tools to sign a PDF:

One of the biggest advantages of these tools is that they work irrespective of your mobile device and its operating system, and you don’t need to install them on your machine to use them.

While this adds convenience, you must be wary of using these tools as using them requires you to upload your PDF. So if it’s some sensitive piece of document that you want to sign, you must avoid using online tools and stick to the offline ones instead.

Easily Sign PDF Documents on the Go

If your work involves working with lots of PDF documents in a day, knowing how to sign them from anywhere can prove to be really helpful. And using this guide, you should be able to easily sign PDFs electronically while you’re on the go, no matter what mobile device you’re using.

Although you’ll also find a bunch of other PDF editing apps on the App Store and Play Store, we feel the apps we’ve mentioned in this guide should suffice most of your document signing requirements.

FAQs About Signing a PDF Document

The process of electronically signing PDF documents varies depending on the kind of device and the operating system it's running. For instance, if you're on iPhone or iPad, you can use the Files app, which comes pre-installed on iOS and iPadOS to sign your PDFs, whereas if you're on an Android device, Adobe Acrobat is one of the best PDF apps to sign a PDF document.

It depends on what device you're using. If you're on iPhone or iPad, you can use the built-in signature tool in the Files app to sign your PDF documents. On the other hand, if you're on Android, you can use Adobe Reader to sign a PDF.

Of course, there are other PDF editing tools—including online PDF signing tools—to sign PDFs too that you can use to sign a PDF.

A few such PDF tools include:

An electronic signature is a digital form of a wet ink signature that is legally enforceable and secure but does not incorporate any codes or standards. It is a symbol, an image, or a process that is attached to a message or a document in order to help recognize an individual's identity and to give consent to use that identity.

Digital Signature, on the other hand, is a secure signature that relies on public key infrastructure and works with Electronic Signatures. In other words, it is an electronic fingerprint that encrypts and identifies an individual.

Digital signatures are preferable to electronic signatures because they are more secure and authentic.

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