How to Sign a PDF on iPhone and Android for Free

Sign PDFs on Your Phone in Under 60 Seconds

You don't need a computer or any app to sign a PDF on your phone. Modern smartphones have built-in tools for basic signing, and free web apps like SignQuick provide a full-featured signing experience directly in your mobile browser.

Here's how to sign a PDF on both iPhone and Android — with three different methods for each.

Signing a PDF on iPhone

Method 1: SignQuick (Recommended — Free, Full-Featured)

• Open Safari and go to [signquick.app/signer](https://signquick.app/signer)
• Tap Upload and select your PDF from Files, iCloud, or email
• Draw your signature with your finger on the signature pad
• Tap on the PDF to place your signature where needed
• Tap Download to save the signed PDF

Why this is best: E2E encryption, SHA-256 seal, audit trail, no app install required. Your signed PDF is legally binding and professionally sealed.

Method 2: iOS Markup (Built-In)

• Open the PDF in Files or tap a PDF attachment in Mail
• Tap the Markup icon (pen in a circle)
• Tap the + button at the bottom right
• Select Signature
• If you haven't created one, draw your signature with your finger
• Tap Done, then position the signature on the document
• Tap Done to save

Limitations: No encryption, no audit trail, no multi-party signing, basic positioning controls.

Method 3: Adobe Acrobat Reader App (Free)

• Download Adobe Acrobat Reader from the App Store
• Open your PDF in the app
• Tap the pen icon → Fill & Sign
• Tap Create Signature and draw your signature
• Tap where you want to place it on the document
• Save or share the signed PDF

Limitations: Free tier limited to basic signing. Advanced features require Acrobat Pro ($10/month).

Signing a PDF on Android

Method 1: SignQuick (Recommended — Free, Full-Featured)

• Open Chrome and go to [signquick.app/signer](https://signquick.app/signer)
• Tap Upload and select your PDF from Downloads, Drive, or email
• Draw your signature with your finger
• Tap on the PDF to place your signature
• Tap Download to save

Works identically to the iPhone version — same encryption, same seal, same legal validity.

Method 2: Google Drive (Built-In)

• Open the PDF in Google Drive
• Tap the pen icon (Edit/Annotate)
• Select the pen tool and draw your signature
• Position it on the signature line
• Save to Drive

Limitations: Basic annotation only — no formal signature field, no audit trail, difficult to position precisely.

Method 3: Adobe Acrobat Reader App (Free)

• Download Adobe Acrobat Reader from Google Play Store
• Open your PDF in the app
• Tap Fill & Sign
• Create and place your signature
• Save or share

Same limitations as the iOS version.

Tips for Better Mobile Signatures

Drawing Quality

• Use your index finger rather than your thumb for more control
• Hold your phone in landscape mode for more drawing space
• Draw slowly and deliberately — rushing makes signatures look jagged
• Prop your phone on a flat surface to keep it stable
• If available, use a stylus or Apple Pencil (iPad) for the smoothest result

File Management

• Save to cloud storage (iCloud, Google Drive, Dropbox) for easy access later
• Name your files clearly: "Contract-ClientName-Signed-2026-04.pdf"
• Email a copy to yourself as a backup
• Check the file size — if it's too large to email (>25MB), use a sharing link

Before You Sign

• Read the entire document on your phone (zoom in on small text)
• Check all pages — don't just sign the last page without reading the rest
• Verify the recipient if someone sent you a document to sign
• Take a screenshot of the completed signing for your records

Mobile Signing vs. Desktop Signing

Bottom line: For quick signatures on standard documents, your phone is perfect. For complex contracts with multiple pages of terms, consider reviewing on a larger screen first.

Is a Phone Signature Legally Binding?

Yes, absolutely. The ESIGN Act does not distinguish between signatures made on a phone, tablet, or computer. A signature drawn with your finger on an iPhone has the same legal weight as one drawn with a mouse on a desktop.

What matters for legal validity:

• You intended to sign (you deliberately drew your signature)
• You consented to electronic signing
• The signature is associated with the specific document
• The signed document is retained and accessible

SignQuick provides all of this automatically, including SHA-256 document hashing for tamper evidence.

Frequently Asked Questions

Do I need to download an app to sign a PDF on my phone?

No. SignQuick works directly in your phone's browser (Safari on iPhone, Chrome on Android). No app download required.

Can I sign multiple pages on my phone?

Yes. SignQuick lets you navigate between pages and place signatures on any page. Use the page navigation arrows to move between pages.

What if the PDF is in an email attachment?

On iPhone, long-press the attachment → Share → Open in Safari → go to signquick.app/signer. On Android, download the attachment first, then upload it to SignQuick.

Will the signature look professional?

Yes. Modern phone touchscreens capture smooth, natural signatures. Take your time drawing, and the result will look just as professional as a pen signature.

Can I send the signed PDF directly from my phone?

Yes. After downloading the signed PDF, tap Share and choose Email, Messages, WhatsApp, or any sharing method available on your phone.