How to Sign a PDF on Android: 3 Free Methods

Android does not have one built-in signature tool that works the same on every phone, because manufacturers ship different apps. But there are free ways to sign a PDF on any Android device. Here are three.

Option 1: Google Drive or Files by Google

Google's PDF viewer, used by Google Drive and the Files by Google app, has added annotation and form-filling features. On recent versions:

1. Open the PDF in Google Drive (or Files by Google).
2. Tap the edit (pen) button. If you do not see it, update the app.
3. Use the pen tool to draw your signature, or the text tool to add a typed name and date.
4. Save. Drive saves the annotated PDF as a copy or in place, depending on the version.

Feature availability varies by app version and device, so if the edit option is missing, use one of the methods below.

Option 2: Adobe Acrobat Reader

The free Acrobat Reader app has a Fill & Sign tool.

1. Open the PDF in Acrobat Reader.
2. Tap Fill & Sign.
3. Tap the signature icon and Create signature.
4. Draw it, then tap where it should go.
5. Save and share.

It works well but asks you to sign in to an Adobe account for some features.

Option 3: a browser editor, no install

1. Open Docento.app in Chrome.
2. Choose the PDF from your Downloads or Drive.
3. Select the signature tool and draw, type, or upload your signature.
4. Place it, add the date with the text tool, and download the signed PDF.

The document is processed in the browser on your phone rather than uploaded to a server for editing, which helps when you are signing something personal like a lease or an employment contract.

Tips for signing on a phone

• Rotate to landscape for a wider signing area.
• Draw large, then resize. Shrinking a big signature makes it look smoother.
• Pinch to zoom before placing so the signature sits on the line.
• Add the date in text, not handwriting, so it is legible.
• Check every page for initials and signature fields before you send.

Troubleshooting

• "Cannot edit this PDF": the file may be protected against changes. Ask the sender for an unrestricted copy, or see PDF permissions explained.
• The form fields do not respond: the PDF may be an XFA form, which most mobile apps cannot fill. See XFA forms explained.
• The signed file is huge: compress it before emailing. See how to compress a PDF on Android.
• The recipient cannot see the signature: flatten the PDF so annotations become part of the page. See how to flatten a PDF.

Is it legally valid?

A drawn or typed electronic signature is accepted for most everyday agreements in many countries. Some documents require a stronger form of signature or a witness. See e-signature laws around the world.

Takeaway

On Android, try Google's own PDF viewer first, Acrobat Reader if you already use it, or a browser editor if you want no install and no account. For iPhone instructions, see how to sign a PDF on iPhone.