How to Sign a PDF on Android: 3 Free Ways

On an iPhone, signing a PDF is built into the system. On Android it is not: there is no single “Markup” tool that every phone has, and what comes preinstalled differs between Samsung, Pixel, Xiaomi and other brands. The good news is that you can sign a PDF on any Android phone for free in a couple of minutes. Here are the three methods worth knowing.

Method 1: Signature Maker (fastest for regular signing)

Signature Maker is a free app made only for signing documents and images. You create your signature once and reuse it.

1. Install Signature Maker from Google Play and open it.
2. Create your signature. Tap + next to Signatures, give it a name (for example “Full signature”), then:
   • Draw it with your finger or a stylus,
   • Type your name and pick a handwriting font, or
   • Scan the signature you already use: photograph it on white paper, crop it and adjust the contrast.
3. Add the PDF. Tap + next to Documents and choose Pick Document/PDF (or Pick from Gallery for a photo of a paper form).
4. Place it. Open the document, go to the page you need, tap Add Signature, drag the signature onto the line and pull the corner handle to resize.
5. Save. Tap Save Document, then keep the signed PDF on your phone or share it by Gmail, WhatsApp or any other app.

On Android you can choose the folder signed documents are saved to in Settings → Save folder.

Method 2: Adobe Acrobat Reader (Fill & Sign)

Adobe’s free Acrobat Reader app has a Fill & Sign tool. You need to sign in to an Adobe account, and the menu names shift slightly between versions, but the flow is:

1. Open the PDF in Adobe Acrobat Reader.
2. Tap the edit (pencil) button and choose Fill & Sign.
3. Tap the signature icon (a pen nib) and choose Create signature.
4. Draw your signature and tap Done.
5. Tap the spot on the page where it should go, then drag and resize it.
6. Tap the checkmark or back arrow to save, then share the file.

Acrobat is a large app with a lot of features beyond signing. It is a good choice if you already use it; if you only want to sign things, a lighter app is quicker.

Method 3: Google Drive’s PDF viewer

Recent versions of the Google Drive app let you draw on a PDF. Open the PDF in Drive, tap the annotate (pen) button, choose a pen and write your signature with your finger, then save. It is free and already on most Android phones.

The catch: Drive does not store a reusable signature, so you draw it fresh each time, at whatever size the zoom level gives you. It is fine for an occasional form, not for regular signing.

Samsung phones: if you have an S Pen, Samsung Notes can import a PDF so you can write on it with the pen and export it again as a PDF.

Which method should you use?

	Signature Maker	Acrobat Reader	Google Drive
Account needed	No	Adobe account	Google account
Reusable signature	Yes, several	Yes	No, draw each time
Typed or scanned signature	Yes	Typed or drawn	Drawn only
Signs photos of documents	Yes (JPG, PNG)	PDFs only	PDFs only
Cost	Free (optional Premium)	Free (paid tiers exist)	Free

Tips for a signature that looks right on a phone

• Sign in landscape. A wider canvas gives a far more natural signature.
• Use a stylus if you have one, even a cheap capacitive one.
• Scan your real signature instead of drawing it. Sign on white, unlined paper with a black pen, then use the Scan option in Signature Maker. See how to scan your signature.
• Keep the size realistic. A signature should be about as tall as two lines of text on the page.

Frequently asked questions

Does Android have a built-in PDF signer?

No. Android has no system-wide signing tool like iPhone’s Markup. Some phones include a PDF viewer with a pen tool (Google Drive, Samsung Notes), but to sign with a saved, reusable signature you need an app such as Signature Maker or Adobe Acrobat Reader.

How do I sign a PDF on Android for free?

Install Signature Maker or Adobe Acrobat Reader from Google Play. Both are free to download and let you create a signature and place it on a PDF.

How do I sign a document someone emailed me on Android?

Download the attachment from Gmail (tap the download arrow), then open it in your signing app. In Signature Maker, tap + next to Documents and choose Pick Document/PDF to find it in Downloads. After saving, share the signed PDF back by email.

Can I sign a photo of a paper document on Android?

Yes. In Signature Maker, choose Pick from Gallery instead of Pick Document/PDF, and sign the photo the same way. See how to sign a photo.

Is a signature added on an Android phone legally binding?

For most everyday documents, yes. In the US, the ESIGN Act and UETA treat electronic signatures like handwritten ones, and the EU eIDAS Regulation recognises them as well. Some documents, such as wills or notarised papers, still need a wet-ink or qualified signature.