How to Sign PDF on Android: 4 Free Methods (2026)

A contract lands in your email. It needs your signature. Ten years ago that meant printing, signing, scanning. Today it takes about a minute on your phone — and it's free.

One thing to know first: there are two kinds of signatures. An electronic signature is your finger-drawn mark on the document — fine for almost everything. A digital signature uses cryptographic certificates to prove authenticity — needed for high-stakes contracts. This guide covers both.

Signing a Paper Document (Scan First)

Sometimes the document starts on paper. The workflow: scan → PDF → sign → share, all on your phone. Adobe Scan (free) turns paper into a clean PDF with automatic edge detection — see our best scanner apps for Android — Xodo's built-in scanner does the same with OCR.

1. Scan the paper with Adobe Scan or Xodo's scanner — check the preview for cut-off edges.
2. Open the resulting PDF in Acrobat Reader or Xodo.
3. Sign using Method 1 or 2 above.
4. Share the signed PDF.

This completely replaces the print-sign-scan cycle. The scan quality from a modern phone camera is more than good enough for contracts.

Filling Forms Before Signing

Most documents need more than a signature — names, dates, checkboxes. Fill first, sign last. In Adobe Fill & Sign, tap any field to type; the app often auto-detects fillable fields. In iLovePDF, the form tools handle text entry and checkboxes together.

Two tips: fill every field before placing the signature (moving text after signing looks sloppy), and use the same font size throughout — mismatched text sizes are the telltale sign of a rushed form. Save a copy of the filled-but-unsigned version too, in case you need to re-sign later.

Method 1: Adobe Acrobat Reader — Fill & Sign (Free)

Adobe's Fill & Sign is free inside Acrobat Reader (4.51 stars, 8 million reviews, 635M+ installs) — no subscription needed for signing.

1. Install Adobe Acrobat Reader and open your PDF in it.
2. Tap the pen icon, then select Fill & Sign.
3. Tap the fountain-pen icon to create a signature. Draw it with your finger, then tap Done. (Tap Clear to redo it.)
4. Tap the fountain-pen icon again, choose your saved signature, and tap-and-hold to place it — drag to position, use the handles to resize.
5. Share the signed PDF via email or any app.

You can also create initials the same way, and fill text fields by tapping them. Your signature stays saved for next time.

Method 2: Xodo — Free, Offline

Xodo (4.17 stars, 476K reviews) has built-in e-signature tools alongside its PDF editing. The advantage over Adobe: it works fully offline, so a sensitive contract never uploads anywhere.

1. Open the PDF in Xodo.
2. Open the annotation tools and choose the signature tool.
3. Draw your signature, place it, resize it.
4. Save and share.

Best for: contracts and legal documents where privacy matters.

Method 3: iLovePDF App — Sign Plus Everything Else

The iLovePDF app (4.61 stars, 346K reviews) lets you fill forms by typing and e-sign with your finger, plus merge, compress, and watermark — useful when the document needs prep work before signing.

1. Open the PDF in iLovePDF.
2. Use the Fill & Sign tools to type into fields and draw your signature.
3. Save and share.

Best for: forms that need filling and signing in one session.

Method 4: DocuSign — When It Needs to Be Bulletproof

Here's the fact most guides bury: signing with DocuSign is free and unlimited. You only pay if you're sending documents for others to sign. If someone emails you a DocuSign link, signing costs you nothing — ever.

Why use it over a drawn signature? The audit trail. DocuSign records who signed, when, and where, with encryption — legally binding under the US ESIGN Act. For NDAs, leases, and sales contracts, that proof matters.

1. Install DocuSign (4.76 stars, 176K reviews).
2. Create your signature once — drawn on your device.
3. Open the document (via email link or upload), tap the signature fields, and sign.
4. Everyone gets a copy automatically.

If you're the one sending: the Personal plan allows 5 sends per month; heavier use needs a paid plan.

Electronic vs Digital Signatures: Which Do You Need?

• Electronic signature (finger-drawn): fine for permission slips, HR forms, delivery confirmations, school documents, most business paperwork. Legally valid under ESIGN/UETA in the US and equivalent laws in most countries.
• Digital/certificate signature: needed when the contract itself demands proof of authenticity — government filings, high-value agreements, anything where someone might later claim "I didn't sign that." Use DocuSign or Adobe's certificate signing.

When in doubt, ask the recipient what they accept. Most of the time, the answer is "just sign it in the app."

Pro Tips

• Use a stylus if you have one — finger signatures look shaky; a cheap capacitive stylus makes a visible difference.
• Rotate your phone sideways — the wider canvas gives your hand more room.
• Save your signature once — all four apps remember it, so the second signing takes seconds.
• Check before sending — zoom in on the signature; make sure it's on the right line and not covering text.
• Keep the signed copy — save the final PDF to Drive before emailing it, and keep the unsigned original separately in case of disputes.

Quick Comparison

• Easiest free: Adobe Fill & Sign — free inside Acrobat Reader.
• Most private: Xodo — works offline, nothing uploads.
• Best combo: iLovePDF — fill, sign, merge, compress in one app.
• Most legally robust: DocuSign — free unlimited signing, full audit trail.

In-Person Signing: Handing Your Phone to Someone

Permission slips, delivery confirmations, visitor logs — sometimes the other person needs to sign on your phone. DocuSign handles this with in-person signing: you prepare the document, hand over the phone, they sign, you get the audit trail.

For casual cases, any of the free apps work: open the PDF, hand them the phone with the signature tool ready, and let them draw. One caution — watch them place it. Signatures drawn by someone else often land on the wrong line, and you'll be the one re-sending.

What If the PDF Won't Let You Sign?

Three common blockers. The PDF is "flat" with no fields: not a problem — Fill & Sign lets you place a signature anywhere, fields or not. The PDF is password-protected: you'll need the password to sign (or ask the sender for a copy without a password). The PDF is certified/locked: some documents are cryptographically sealed against changes — in that case only the sender can modify them, and you'll need to request a signable version.

If the app says the file is "read-only," check whether it opened from a restricted location (some email attachments open in preview mode). Save it to your files first, then open it in the signing app.

Storing Signed Documents

A signed PDF is a legal record — treat it like one. Save the final version to cloud storage (Drive, Dropbox) immediately after signing, not just in the app's local folder. Name it clearly: "contract-signed-2026-10-05.pdf" beats "document(1).pdf" when you need it in six months.

Adobe and DocuSign both offer cloud storage for signed documents — useful if you sign often. For everyone else, a dedicated Drive folder ("Signed Documents") with consistent naming is enough. And keep the unsigned original too, separately — if a dispute ever arises, you want both versions.

Is It Valid in My Country?

Electronic signatures are recognized in most of the world: the US (ESIGN Act, UETA), the EU (eIDAS regulation), the UK, Canada, Australia, and many others. The details vary — some countries require certificate-based signatures for specific document types (real estate, wills) — but for everyday business paperwork, a finger-drawn signature in a reputable app is accepted.

The practical rule: the recipient's acceptance matters more than the law. If your bank, landlord, or employer says "sign in DocuSign," do that. If they say "just sign the PDF and email it back," any method here works.

Signing Multiple Documents at Once

Onboarding packets, tax season, rental applications — sometimes it's ten PDFs, not one. The workflow: merge first, then sign once. Combine the documents into a single PDF (see our guide on merging PDFs on Android), then place your signature wherever each document needs it.

This beats signing ten separate files and keeps everything in one shareable document. Just make sure each document's signature line is clearly visible after merging — check the page boundaries before you start signing.

Final Verdict

For everyday signing, Adobe Fill & Sign is the answer — free, from the company that invented PDF, already on hundreds of millions of phones. For sensitive documents, Xodo keeps everything offline. And when the signature needs to hold up in a dispute, DocuSign's free signing gives you the audit trail. Either way: stop printing things to sign them. Your phone does it faster, cheaper, and leaves a better paper trail than the printer ever did — permanently.

Frequently asked questions

How do I sign a PDF on Android for free?

Use Adobe Acrobat Reader's free Fill & Sign: open the PDF, tap Fill & Sign, create your signature by drawing with your finger, drag it into place, and share. Xodo and iLovePDF offer the same free.

Is a signature drawn on a phone legally valid?

Yes, in most cases. Electronic signatures carry the same legal weight as paper ones under laws like the US ESIGN Act. For maximum proof, use a service like DocuSign that records an audit trail of who signed when.

What is the difference between electronic and digital signatures?

An electronic signature is any mark of intent — including a finger-drawn signature. A digital signature uses cryptographic certificates to prove authenticity. For everyday forms, electronic is enough; for high-stakes contracts, use certificate-based signing.

Is DocuSign free?

Signing is free and unlimited — you can sign any document sent to you at no cost. Sending documents for others to sign requires a paid plan (Personal allows 5 sends per month).

Can I sign a PDF without printing it?

Yes — that's the entire point. Draw your signature with your finger in Adobe Fill & Sign, Xodo, or iLovePDF, place it on the document, and share it digitally. No printing or scanning needed.