How to add your signature on a PDF document using only your Android phone

We recommend 2 apps for signing PDF documents on Android, but feel free to mention alternatives in the comments section, if you know any good ones.

Jump to: Guide to PDF signing with Adobe Acrobat Reader, Guide to PDF signing with Adobe Fill & Sign DC, Alternatives.

These 2 apps are both from Adobe, the first one being Adobe Acrobat Reader and the second one, Adobe Fill & Sign DC. Both are free, with Adobe Acrobat Reader being the one with extra signature features — such as using a photo of your signature or different colors for it, while Adobe Fill & Sign DC gives you more options in terms of PDF creating — it can basically turn photos into PDFs using existing photos, or from newly taken photos. More details on these features in due time.

How to sign a PDF with Adobe Acrobat Reader (step by step guide)

You're basically going to open a PDF file in Adobe Acrobat Reader, add your signature to it using a built-in option, then use the Share option in order to email or save the signed PDF document.

Step 1: Download Adobe Acrobat Reader.

Step 2: Open a PDF file.

Adobe Acrobat Reader's menu looks like this on Android:

Create PDF, Export PDF, and Organize pages are paid options, while Fill & Sign simply redirects you to the second app mentioned in this tutorial, namely Adobe Fill & Sign DC.

My Documents is where you want to be in order to open a PDF file. Surely, if you opened the PDF straight from your email or from a File Explorer, you'll have the 'Open with' Android pop-up asking you which app you wish to use and from there, you can simply pick Adobe Acrobat Reader.

In the Recent tab of 'My Documents' you'll see the latest PDF files you opened, along with an 'Open" button, in the bottom right. Tap Open and you'll see an Andoid pop-up asking you which app you wish to use in order to browse for files. I have several explorer apps installed on my phone, so I get these options below. ES File Manager or Total Commander should do the trick here.

The Local tab lists all PDF files from your Android phone, as Adobe Acrobat Reader scanned for them when you opened it.

You also have the option to load a PDF file from your Adobe Document Cloud or Dropbox, which is quite convenient. No dirrect integration with Google Drive or OneDrive, but you can easily open Google Drive or OneDrive, browse to a PDF file there and tap 'Open with...', thus having the option to load that PDF file in Adobe Acrobat Reader for Android.

Step 3: Add your signature on the PDF document

Once you opened a PDF document, you're in the 'Viewer' part of the app. It should look like this:

Screenshot showing a Sample PDF along with actions at the bottom.

At the bottom of the screen there should be 3 actions: View, Comment, Share. If you don't see them, tap once on the PDF.

Tap on Comment and you'll see a new set of actions at the bottom.

Use the one on the far right, which looks like a pen, in order to add your signature.

You'll be prompted to tap where you want to add your signature. Don't worry, you don't have to be extremely precise at this point, as you get options to edit the signature placement later on.

If this is the first time using the app, the next screen will turn into landscape mode and you'll several options there:

• the main option is to simply use your finger and sign on the screen
• at the bottom you can use either your camera to take a picture of a paper where your signature exists, or use a picture with your signature, already present on your phone; if you choose any of these 2 options, you then get a 'Crop' option next, which allows you to select only the signature part from your photo
• you also get a 'Save Signature' toggle, bottom left

Use any option you find appropriate. If you decided to save the signature for future use, from now on, every time you hit the 'Add signature' button, you'll re-use this exact same signature.

Example signature obtained by simply signing on screen - misspelled :)

After you draw your signature or picked it from a photo, you'll see it displayed on the PDF.

Tap on it and you'll see resize, move, and delete options. If your signature was finger drawn, you can also pick a basic color. You get: white, black, gray, purple, blue, cyan, light green, dark green, yellow, and red. If the signature was created from a photo, you don't get the option to change colors.

Step 4: Email or Save your signed PDF document

Tap Back on your Android phone, in order to get to the previous menu. Now, you can use the 'Share' button at the bottom of the PDF file. There you have options to email the PDF file, save it on your phone, save it on Google Drive, send it via Bluetooth, send it to Skype, WhatsApp, and more options according to the apps you have installed on your phone.

On the left: Sharing options, On the right: Signed PDF shared to Gmail

If you use the top right 3-dots menu, you'll have the Print option as well.

Once you hit back one more time, or exit the Viewer menu, the document will be permanently saved, with your signature on it. Adobe Fill & Sign DC, the next app we're covering, will keep the PDFs editable and you can revert changes at a later time.

How to sign a PDF with Adobe Fill & Sign DC (step by step guide)

What we're basically doing here is open or create a PDF file in Adobe Fill & Sign DC, add your signature to it using a built-in option, then use the Share option in order to email or save the signed PDF document.

Step 1: Download Adobe Fill & Sign DC.

Step 2: Open or Create a PDF document

The main menu for Adobe Fill & Sign DC looks like this:

On top right you have Profile and Signature buttons. The Profile button allows you to create a profile with details such as name, address, contact info, dates. These can be used to easily fill-in forms on PDFs, besides just adding a signature. The Signature button allows you to create a Signature and Initials.

As a side note, besides applying these actions to a PDF, you can also tap anywhere on it and you'll see that you can add words on the spot, as well as a check mark, X mark, and middle dot.

At the bottom you'll see a list with a few recent PDF forms and the option to View all.

In the very center, and this is where we'll start, you can tap 'Select a form to fill out' in order to either open a PDF file, or create one using images on your phone or from new ones taken with your camera right there on the spot.

If you choose to create a PDF from images, you get basic options such as rotate, auto-enhance and more importantly, a handy Crop, which is more of a freestyle Crop because it allows you to Crop choosing the corners of the documents you captured with your camera. You can also add multiple pages and re-order them.

The Crop feature in action

Extra tip: If you're looking to scan documents using your phone's camera and then create PDF files from them or from existing pictures, a nice alternative is Tiny Scanner (also on iOS).

Step 3: Add your signature on the PDF document

Once you opened a PDF file, simply tap the top right Signature button in order to add your Signature and/or Initials.

If this is the first time you are using the feature, you'll be prompted to a landscape oriented screen in order to create your Signature or Initials. Here you can draw them by hand or more accurately put, by finger. You can't add signatures from images, like you could with Adobe Acrobat Reader above. Tap Save once you finished drawing and then tap the Pen button again and choose Signature or Initials to be added to the document.

The Signature or Initials can be moved around the PDF document and resized as needed. You can't choose colors — they will simply be black.

Step 4: Email or Save your signed PDF document

Tap the top Share button and you'll see the same sharing options as above with Adobe Acrobat Reader. You can email the PDF file, save it on your phone, save it on Google Drive or OneDrive, send it via Bluetooth, send it to Skype, WhatsApp, and more options according to the apps you have installed on your phone. Note that for some of these options to exist, you need to have the corresponding app installed. For example, in order to save a signed PDF to Google Drive, you need to have the Google Drive app installed on your phone.

Alternatives

DocuSign (also on iOS and Windows) and SignEasy (also on iOS) are well worth checking out. Both require signing up for an account. DocuSign offers no monthly limit for signing PDFs with its Free plan, which is buried deep in its website. SignEasy only allows for 3 PDFs to be signed with its Free plan. For more, you need a paid plan.

That's it. Got anything good to add? Leave a comment.